Frank Lampard admits he is concerned about football in England continuing while the COVID-19 crisis escalates.

On Friday, London's mayor, Sadiq Khan, declared a "major incident" in the capital as hospitals face rising numbers of patients.

The English football authorities are carrying out regular tests on players and club staff, and the number of positive cases is rising, with 40 declared in the Premier League for last week.

Lampard said none of those were Chelsea players but confirmed "a small number of staff" with the London club had tested positive recently.

Sunday will see Chelsea welcome fourth-tier outfit Morecambe to Stamford Bridge in the FA Cup third round, with the visitors having recently had to postpone two games because of coronavirus cases in their ranks.

Chelsea head coach Lampard was asked about possible worries, and said: "Not just about playing Morecambe, but I do have concerns because of the current climate.

"We haven't had any players positive in the last couple of rounds – we have had a small number of staff.

"Of course, whilst the country is in lockdown for a reason, while football carries on for a reason, it means there's lots of mixing going on.

"We have to be ultra-careful. I'm not completely comfortable but we have to toe the line, we have to keep playing.

"The safety must come first. There are lots of moving parts and things are changing day by day, week by week."

Burnley boss Sean Dyche this week floated the idea that if footballers were vaccinated, it would lead to savings on testing and such money could be ploughed into the National Health Service.

Lampard said, as Dyche did, that footballers should not be seen to be jumping the queue ahead of those in most need.

He said: "Maybe there's a time down the line when we look at sports but I don't think it's that time right now."

Chelsea will be without the injured Reece James, Andreas Christensen and N'Golo Kante for the Morecambe game, and Lampard is considering giving a first-team chance to a number of academy players.

Lampard's team have lost 3-1 to both Arsenal and Manchester City, either side of a 1-1 draw with Aston Villa, in a Premier League slump over the past fortnight.

Previous defeats in mid-December to Everton and Wolves have also played a part in them falling away from being challengers near the top of the table to sitting in ninth place.

They face a fourth-tier side who have won six of their previous seven games, yet this is Morecambe's fourth appearance in the third round of the cup, and they have lost each of their previous games at this stage without scoring.

Chelsea's last third-round defeat in the competition came in 1997-98, when they lost to Manchester United.

Lampard said the challenge of returning his team to peak form "makes my job more exciting".

He accepts "confidence has been hit" and said: "The players need a lift. That's my job, the staff's job, and their job. I don't know any way out of a lack of confidence but to sprint yourself out of it and fight yourself out of it, because those are the rules of football."

He was reminded about Chelsea being stunned 4-2 by Bradford City in the fourth round in January 2015 and said: "Underdogs will turn up, try to win and make things difficult for you.

"Considering our current form, we have to be even more on guard and worry about ourselves, and get ourselves playing well, because if we play well and do our job right, we'll win the game I believe."

Jose Mourinho warned Tottenham would be left in an "impossible situation" if their game at Aston Villa is postponed due to a COVID-19 outbreak and called on the Premier League to show "leadership".

Villa are expected to field a young side in the FA Cup third-round tie against Liverpool on Friday, as a large number of first-team players and staff tested positive for coronavirus this week.

Spurs already had a derby at Fulham called off on December 30 after the Cottagers were hit by the virus and a scheduled trip to Villa Park next Wednesday is now in doubt.

Tottenham will also face Manchester City at a later date of April 25 due to the pandemic and given they are fighting for honours on four fronts, Mourinho suggested they would refuse to accept any more postponements.

Speaking ahead of Sunday's FA Cup tie at Marine, he said: "I believe that is a completely impossible situation for a club to have three matches postponed, especially if that club plays in Europe. If that club doesn't play in Europe, of course there are the UEFA fixtures.

"For a Europa League team to have three matches postponed is impossible. Completely impossible. That's the only thing that I can say."

Asked about the prospect of facing Fulham instead of Villa, he added: "I don't know. It's not for me to find solutions. I'm not going to lie to you, I've been doing that hypothetical exercise with my staff.

"Of course, we have no influence and we don't want to have influence. The only thing that we can say is that what we did in the beginning of the season is impossible to repeat and we refuse to repeat.

"We have to defend our players, the integrity of our competitions and we would never accept to play seven matches in three weeks like we did before. One thing is [the] beginning [of the season], another thing is mid-season.

"And also because of the difficulties and demands of the matches. One thing is to play with all the risks, the Europa League play-offs, another thing is to play Europa League knockout where all the best teams are there.

"We cannot be put in an impossible situation. To have three matches postponed... it is the moment for the Premier League to show leadership, make decisions, that of course a club like us, is trying every day to be ready to play, to follow the rules that we had in our hands.

"We cannot be punished. If we don't play against Aston Villa, we will have three matches postponed and that is impossible. Because after the season we have the Euros, and of course the matches cannot be moved."

Mourinho revealed Gareth Bale trained on Friday and could travel to eighth-tier minnows Marine, while Jack Clarke and Harvey White will be in the squad.

Mikel Arteta knows how he wants to improve Arsenal's squad this month but warned the transfer market is "very complicated" in the current climate.

Julian Brandt is among the reported targets for the Gunners during the January window, although Borussia Dortmund sporting director Michael Zorc insisted there had been "no offers at all" for the midfielder.

Arsenal boss Arteta this week revealed Mesut Ozil could be on the move after DC United and Fenerbahce were linked with the out-of-favour playmaker.

The London club allowed Sead Kolasinac to return to Schalke, but there has been very little transfer activity just over a week since the window opened.

Arteta would like to do get his business done early in the window, but in a week that saw Arsenal take a short-term £120million Bank of England loan due to the impact of the coronavirus crisis, the Spaniard is being realistic with his expectations.

Asked about the prospect of making early signings, he said ahead of the FA Cup third round tie with Newcastle United on Saturday: "I don't know. At the moment the market is really complicated and the situation around every club is not easy.

"To get the negotiations going it's not easy, it makes it harder because you can't be face-to-face and you cannot travel to another country to make that happen, it has to be on the phone or Zoom.

"It can go either way. I can tell you what I would like, with the players out and in sorted, but I think it's really complicated."

Arteta says it is important to understand that players may want to move on due to the pandemic.

He added: "It's affecting everything. It's affecting things transfers financially, it's also affecting some players who are here and they are stuck here for a year and realise 'I need to go back home, I need my family to be happy, to be next to me'.

"It's a bit of a mixture, but players are experiencing different feelings that probably are new to them and that's why I keep insisting this virus is about mental health as well as how you are feeling physically. Mental health is a big, big thing that we have to pay more attention to."

One player who has arrived at Arsenal is 19-year-old defender Omar Rekik, who joins the under-23 squad from Hertha Berlin.

Jurgen Klopp says he has no problem with Liverpool not dipping into the transfer market in January as owners Fenway Sports Group are only acting in the best interests of the club. 

The Premier League champions have been badly depleted this season, particularly in the heart of their defence with Virgil van Dijk and Joe Gomez long-term absentees and Joel Matip struggling to stay fit. 

Klopp is unlikely to add to his squad during the mid-season window, but the Reds boss understands it is difficult to do business at this time even without the financial impact of the coronavirus pandemic. 

The Liverpool boss insists he is on the same page as club ownership, no matter the key absences that could undermine their push for trophies. 

"In good times everyone thinks our owners are really generous – 'My God, big signings, whatever’ – and in bad times everyone thinks they are really tight – maybe because they are from a different country – but they are not, they are absolutely concerned about the club and success of the club," Klopp said. 

"And that is an understanding how we have it. They see exactly the same things I see about necessity of players and stuff – it's not that I say 'By the way a centre-half would be really nice’ and they say, 'Wow, a centre-half. Really? Why?' 

"It is all clear, all on the table, we work on that. It is the situation and on top of that we have January, not the easiest transfer window, having not the money exactly like we want. 

"It is a window where other clubs say, 'No, we have enough [money] to survive' so we don't do anything on our targets. 

"It is nothing to do with worrying [about whether it will impact their chances of winning trophies] or not. These are the facts.

"My job is to deal with the circumstances which I always do. If the world would be in a completely normal place, we would try everything to do the right stuff now but the world is not in a normal place so I don't know why we constantly try to treat the football like it is independent of other issues around."

Liverpool are due to be in FA Cup action on Friday, though their tie with Aston Villa is in doubt due to a coronavirus outbreak in their opponents' camp.

Villa announced on Friday they had closed their training ground as a consequence, while the Football Association will make a decision on whether the game goes ahead following further testing.

The Football Association (FA) is still hopeful Aston Villa's meeting with Liverpool can go ahead as planned on Friday, with a final decision to be made after further coronavirus testing.

Villa announced on Thursday they had closed their Bodymoor Heath training ground after "a significant coronavirus outbreak" at the club, with first-team training cancelled after players and staff returned positive results.

Their FA Cup third-round clash with Premier League leaders Liverpool was consequently thrown into doubt, though it is hoped the fixture will not have to be postponed.

An FA statement read: "The Football Association and Aston Villa are working closely together to try to ensure that the club's FA Cup third round proper fixture with Liverpool can go ahead as planned at Villa Park.

"Final confirmation will be made tomorrow pending the results of additional COVID-19 testing."

It was announced earlier on Thursday that the third-round clash between Shrewsbury Town and Southampton would not go ahead on Saturday after "several" members of the League One side returned positive coronavirus results.

Derby County this week revealed they will select a side made up of Under-18 and Under-23 players for their tie at non-league Chorley on Saturday, with interim boss Wayne Rooney and his first-team squad staying at home following a coronavirus outbreak at the Championship club.

Liverpool are set to stick with their threadbare options at centre-back rather than recruiting a January replacement for Virgil van Dijk or Joe Gomez. 

The Reds have played much of the season so far with midfielder Fabinho in defence alongside a rotating cast of partners after long-term injuries to their starting duo. 

Joel Matip has been limited to just eight Premier League appearances due to his own fitness issues and is facing a race to be back for a vital game against Manchester United next week. 

Academy graduates have stepped in, with Nathaniel Phillips playing three times and Rhys Williams twice in the league, while captain Jordan Henderson lined up at centre-back in Monday's defeat to Southampton. 

Although Henderson and Fabinho won nine of the 11 duels they contested between them in that match and still ranked second and third for total touches, it is not an ideal fix. 

And such issues have prompted reports of interest in Schalke's Ozan Kabak and Lille's Sven Botman, although The Athletic reported on Thursday that Liverpool will not pursue either option in the mid-season window. 

Jurgen Klopp said prior to the game against Southampton that the club would do "the right thing" this month - and that appears to mean opting against a new signing. 

Asked if he could rule out a transfer as he previewed the scheduled trip to Aston Villa in the FA Cup, Klopp replied: "I cannot say definitely we will not bring one in. It's just not likely because of the situation in the world. 

"We should not forget that the [coronavirus] situation is a tough one for all people and for football clubs as well.

"There might be some clubs with absolutely no financial problems, but this club always was and will always be - with these owners, for sure - very responsible with the things we do. 

"If the world would be in a normal place, everything would be fine, we won the league, won the Champions League, the club is in the best possible situation, and you have three senior centre-halves all injured, is that a situation where you would normally do something? Yes, definitely. 

"But we are not in that situation, so I don't know if something will happen or not. 

"We maybe could do something, but it would be a short-term solution and we don't have a short-term solution, so it's not right because it does not help. 

"We have to get through this. It's not the best moment for the whole planet, so why should it be for this football club?" 

While rotation has been enforced in the middle of the defence, full-backs Trent Alexander-Arnold and Andy Robertson have remained automatic picks. 

Alexander-Arnold tested positive for COVID-19 in pre-season and has also battled a calf injury, yet has still played 15 of Liverpool's 17 league matches. 

The right-back's performance level has dipped this season and his first error leading to a goal handed Southampton a 1-0 win on Monday. 

There was criticism of Alexander-Arnold after that match, in which he was substituted, and Klopp acknowledged on Thursday it was "not his best game", though backed the England international to recover. 

"The reason is he was out for a while with COVID and had an injury which didn't help," Klopp said. "He had no pre-season really. 

"Then with the quality he has and the situation we were in, he played pretty early. He's now getting there. 

"Physically he's fine, he just has to find his top shape again, and that will happen sooner rather than later."

Aston Villa closed their training ground on the eve of Friday's FA Cup third-round clash with Liverpool due to a "significant" coronavirus outbreak.

Villa on Thursday revealed a large number of first-team players and staff are isolating after testing positive for COVID-19 this week.

The first team did not train the day before they are due to face Premier League champions Liverpool at Villa Park and talks are being held over the scheduling of the tie.

"Aston Villa can confirm that the club has closed its Bodymoor Heath training ground after a significant coronavirus outbreak," a club statement said.

"A large number of first team players and staff returned positive tests after being routinely tested on Monday and immediately went into isolation.

"A second round of testing was carried out immediately and produced more positive results today.

"First team training ahead of tomorrow's FA Cup match with Liverpool was cancelled.

"Discussions are ongoing between medical representatives of the club, the Football Association and the Premier League."

Jurgen Klopp acknowledged Liverpool are enduring a tough run but insisted performances have not been as bad as results suggest.

The defending Premier League champions are top of the table again but have won just two of their past six matches – and two of seven in all competitions.

Rivals Manchester United, who have a game in hand, have moved level on points with the Reds at the summit ahead of the two sides meeting next weekend.

"We were not waiting for [this run of form] and we do not enjoy it, but it's not unlikely that these kinds of things happen," Klopp told a news conference on Thursday.

"I think we only won two of the last six – that's not the standard we expect from ourselves, obviously.

"So, we don't take it easy, but we still see what we can improve, what we have to improve, and don't think everything was bad in the last few weeks.

"The league is too strong, and if you struggle a little bit, immediately the results go the other way because the opponents are fighting with everything they had. You saw that against Southampton [a 1-0 defeat on Monday]."

Liverpool must first focus on the FA Cup, however, with Aston Villa hosting Klopp's men in the third round on Friday.

Last season's run to round five was Liverpool's best under Klopp, with the Anfield outfit eliminated from four of their past six ties against fellow Premier League sides, only beating Everton (in 2018 and 2020) in this time.

The Reds had reached the semi-final in the final season before Klopp's appointment, losing to Villa in the last four to end a six-match winning run against Friday's opponents in the competition.

Despite his underwhelming record in the competition, the manager says Liverpool have always been determined to succeed.

"It's important. It's the FA Cup," he said. "We didn't go far so far in this competition.

"I didn't think we were blessed so far with sensational draws so far and now we go to Aston Villa, which is a tough one as well.

"We always took it very seriously and will do this time as well, but we cannot forget the intensity of the period we are in and all these kinds of things.

"It's important – football games are important. We are professional football players or coaches or managers and the only thing we have to do is to win football games and to try to make sure that we really can do that. It's a very important competition, so we will try to win that."

Liverpool were beaten 7-2 by Villa in the Premier League this term, shipping seven goals in a single match in any competition for the first time since 1963.

Klopp is therefore reluctant to name a weakened team, even with the United game on the horizon.

"We need to find the balance to field a team where we didn't change too much," he said. "We bring in fresh legs again.

"The rhythm [for returning players] is a different issue. That's step by step. We cannot do that in one game. We can't use the FA Cup to give players rhythm – the opponent is just too strong for that.

"After the Aston Villa game, we have eight days between Villa and Man United, so that's a long training week where we can do a lot of stuff in 11-v-11 situations, which will help the players a lot, especially the players who were out for a while. After that, we will be in a different place."

Pressed on specific injuries, Klopp added Naby Keita would return "soon" but not this weekend and Liverpool "will try" to have Joel Matip back for Manchester United, although Diogo Jota is still wearing a brace on a damaged knee.

Son Heung-min scored his 100th goal for Tottenham in all competitions as he netted against Leeds United, with Harry Kane the provider once again.

The South Korea forward, who moved to north London in 2015, has been in sensational form in 2020-21, and moved onto 99 Spurs goals with a cool finish on the break at Liverpool in December.

Son drew a blank in his next three outings, failing to find the target as Spurs went down 2-0 to Leicester City, before he had a goal disallowed in an EFL Cup win at Stoke City and then only managed one attempt at goal in a 1-1 draw with Wolves on December 27.

However, after Wednesday's scheduled game with Fulham was postponed, his landmark effort came against Leeds on Saturday.

Kane – who has now assisted nine of Son's 12 Premier League goals this term – whipped in a brilliant cross from the right, which his strike partner swept home first time.

Son's strike put Spurs 2-0 up just before half-time, with Kane's penalty having put Jose Mourinho's men ahead.

With 169 goals to his name, Kane is the only Spurs payer to have netted more goals than Son since September 2015.

It was also the 13th time Kane and Son have combined for a goal this season, which is a joint-record in a single Premier League campaign.

Son has scored 65 of his 100 Spurs goals in the Premier League – 35 coming from his right foot, 25 from his left, and the remainder with his head.

The former Bayer Leverkusen forward has also supplemented that tally with a further 33 assists, while he has scored 15 times in the FA Cup and EFL Cup.