Thomas Tuchel warned Chelsea cannot afford to trim their squad before the transfer window closes after losing hamstring injury victim N'Golo Kante for "several weeks".
The head coach would be prepared to consider player exits if he can bring in top-class replacements, but until then the likes of Christian Pulisic and Callum Hudson-Odoi will be staying.
That was the firm message from the Blues boss on Friday, two days out from his team's trip to Leeds United in the Premier League.
He said Kante's injury, sustained in last week's thrilling 2-2 draw with Tottenham, was "quite serious".
"We're talking about weeks, which is not good news," Tuchel said. "We're disappointed and sad because N'Golo was super important and super fit, and he will be out for several weeks."
Armando Broja and Mateo Kovacic are also out of contention this weekend, and while it has been mooted that Chelsea are open to loaning out some first-team players, Tuchel is adamant that should not happen at the moment. Pulisic has been linked with Manchester United.
"We will not comment on our players and will not encourage our players to go out in the moment," Tuchel said
"If I put the chin a little bit up and look at the schedule which is coming, with Southampton during the week and two Champions League matches ... it's coming, it's in front of the door, we will need a lot of quality players to be competitive."
Tuchel's outlook will change if Chelsea can corner their targets and bring them to Stamford Bridge.
"We work together about the reinforcements, but it's never easy," said the German. "It's not that we can wish for something and it will happen. As long as the transfer window is open, there are always possibilities."
Having loaned out Romelu Lukaku to Inter, Chelsea are lacking a proven striker in the number nine mould. The likes of Raheem Sterling and Kai Havertz could do a job there, and may have to on a regular basis if Chelsea cannot sign a targetman.
"I believe we can compete with this group, but to be very honest it's one thing to compete once a week and another thing to compete 60 times in a year and three times in a week," Tuchel said.
"For this you need a strong group, and you need players who challenge for their place and their minutes and push each other to the highest level.
"We are very happy about the performance, and we are still active in the market, and we know what can be possible, but if not we will make the very best out of it.
"If we are looking, we're looking for high quality, and we're looking for personality that suits our group and suits our club, and nothing has changed."
Chelsea won 3-0 at Elland Road last season but surprisingly have never won consecutive away league games at Leeds. They were last beaten by the Yorkshire side in December 2002, when a 2-0 loss at Leeds was incurred after an own goal from William Gallas and a strike from a 16-year-old James Milner
Chelsea hoped Broja would be making an early-season impact after returning from his loan to Southampton, but the 20-year-old Albanian striker is on the injured list for now.
"We know enough about him, but it's one thing to perform on a loan and another to perform in a club like Chelsea," Tuchel said. "He's injured again, and that does not help his own ambitions and does not help us in having a clear view of what he can give us.
"Given the size of the squad at the moment, I would say it's a huge chance for Armando to have an impact at Chelsea. I understand this is his clear ambition, his clear goal to make this step here. He has our support, but unfortunately it's the second time he's injured in a short period of time, and he's held back for that reason."