Ronald Koeman backed Antoine Griezmann but said goals would be the "best medicine" to boost the Barcelona forward's confidence.

Griezmann's last goal came against Ferencvaros in the Champions League on December 2, and he has just three in 16 LaLiga appearances this season.

A trip to Los Carmenes to face Granada on Saturday could help the France international, who has been involved in four goals (three goals and one assist) in his past five visits to the ground in LaLiga.

Barcelona coach Koeman said while Griezmann was working hard, goals would be best for the 29-year-old.

"Any player needs confidence in himself, his team-mates and the place where he plays. This starts with the player," he told a news conference.

"As a coach, I can communicate with [Griezmann], show him things and footage of potential things to improve, but at the end it's the player who has to show his quality and give effectivity to the team.

"It's not the case that Antoine doesn't work, he works a lot in any position. The other day he recovered a lot of balls, he gave an assist to Leo [Messi].

"But it's time that he scores, because scoring goals is the best medicine to have total confidence in yourself."

Griezmann has converted just 22.2 per cent of his big chances in LaLiga this season, his lowest in any campaign since at least 2012-13.

Barcelona are fourth in the table, seven points behind Atletico Madrid but having played two more games.

Ronald Koeman is keen to bolster his options at Barcelona with some January additions, but he acknowledges the club's financial situation may make it too difficult.

Philippe Coutinho last week joined Ansu Fati, Sergi Roberto and Gerard Pique on Barca's long-term injury list, while Carles Alena was allowed to leave for Getafe on loan until the end of the season.

Koeman has already expressed his desire to add a striker to his ranks, with the club having let Luis Suarez leave in the close season without signing a replacement, and they continue to be linked with Memphis Depay.

However, Barca's finances have been hit hard by the coronavirus pandemic, so much so that they have delayed the biannual wage payment due to players in January.

Koeman consequently accepts it may not be possible for Barca to fulfil his wish to bring in new faces.

"It is important for our short-term future. We want to improve the squad. I still think some positions need more competition and effectiveness," said Koeman on Friday.

"But I understand the situation of the club. If it is not possible, it is not possible, and we will wait for the next window."

Koeman suggested Alena may not be the only young player to leave Camp Nou this month, though he revealed 17-year-old midfielder Ilaix Moriba could be in line for a first-team debut against Granada on Saturday.

"We have told the players that I think it is better for them to find a way out so they have minutes, predominantly [these suggestions have come from] Ramon Planes [club technical secretary] because I am more focused on the games," said the Dutchman.

"Once again it is the player's decision. I think that for some, without mentioning names, because of their youth it is best to seek the best as a player. A young man cannot go a year without playing. It's not good for improving as a young player.

"We know that with Alena's loan we are missing a player, and Ilaix was with us in pre-season. Sometimes he trains with the first team. It is a possibility he will be called up for tomorrow's game."

Barca will be without the suspended Clement Lenglet at Nuevo Los Carmenes and Koeman indicated Samuel Umtiti could make his first start of the season in his fellow Frenchman's stead.

"He has been out for a long time and has recovered from his injury. It's a long path for him to be as he was before," said Koeman.

"He has had some minutes and we have to make a decision. Without Lenglet, he and [Oscar] Mingueza can deliver. We will make a decision after training today."

Following their meeting with Granada, Barca will compete in the Supercopa de Espana and the Copa del Rey.

In the latter competition they were drawn against fellow Catalan side Cornella, who remarkably knocked out LaLiga leaders Atletico Madrid on Wednesday.

"I am not surprised. There are surprises like this in all countries," Koeman said of Atleti's defeat.

"It can be a complicated game. They deserved to win against Atletico, who played with a strong team. If it's not your day, a lower team with motivation and dedication can make things complicated for you.

"It's a nice tie because we don't have to travel, but we have to adapt to the artificial pitch. There are other games that we have to have maximum attention on first, though."