The Blues have seen their title hopes founder in recent weeks amid a raft of players being unavailable, the most difficult of which to control have been for coronavirus-related reasons.
Andreas Christensen became their latest player to test positive for Covid-19 ahead of Saturday’s defeat at Manchester City.
While N’Golo Kante and Thiago Silva returned from isolation, Christensen’s absence exacerbated Tuchel’s problems with Trevoh Chalobah, Ben Chilwell and Reece James still out injured and Edouard Mendy at the Africa Cup of Nations.
The situation has been of huge frustration to Tuchel and he feels it has been costly. The London club were firmly in the title race a month ago but this weekend’s 1-0 loss at the Etihad Stadium has left them 13 points behind the champions.
Brighton will be a tough test for Chelsea on Tuesday night. Albion have played some decent football of late and were the better team when they drew 1-1 with Tuchel's men at Stamford Bridge last month.
Tuchel believes getting players back from injury and illness is more important than adding to the squad in January.
He said: “Of course we will try to improve but if you mean do we need other players, I think we just need our whole squad.
“Were Liverpool able to compete last year for the title? No. The only real difference was that they were lacking Virgil Van Dijk.
“I’ve said it many times, key players are key players because they are key in everything they do and every way in which they behave.
“Our team is a strong team and I love the ambition, I love the attitude and hunger with which we are playing. We are still brave and we are still up for a good fight, and you can trust anyone you put on the pitch. It’s a pleasure to be at the sideline.
“But it’s different if, as a player, you have to fight every single day for your place, and this is not the case in our team for too long. If you have a negative test and you are fit you have huge chances of being in the line-up.”
Tuchel insists he is not making excuses for his side’s failure to maintain their challenge – they have won just one of their last six in the league – but does feel circumstances have conspired against them.
The German said: “To compete and do what we need to do for 90 minutes, we need everyone and we’ve struggled because of long-term injuries and Covid.
“Still we are reliable and still we want to push ourselves, and still we will not make excuses. It’s just to explain the situation.”
Brighton are without Yves Bissouma who is at the AFCON with Mali and Enock Mwepu is struggling with a hamstring issue. Adam Lallana is also a doubt after hobbling off in the second half against Crystal Palace on Friday night.
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