Chelsea manager Rafael Benitez has said that he wants to sign new players in January.
The Spaniard warns that if his squad is not reinforced next month, his players will face burnout from playing too many matches.
"Anyone can see the team needs to improve a bit physically," he said. "But you cannot do that if they play two games in a week.
"If you're not winning and you analyse the players who have played every game, there aren't many players here. There were 19, now 20 with [Marko] Marin. They'd been playing fewer players.
"I'm not here to criticise, but that's the reality. They'd played so many games, two a week - and massive games in the Champions League."
Benitez added that he has already told Chelsea owner Roman Abramovich about the problem.
"The players were getting tired," he continued. "You can't give them a rest, either, because there's no time.
"I told the owner this. We had a board meeting on Thursday and I explained what I'd seen, told them my ideas and gave them my explanation.
"They asked me my opinion on what we need (in terms of signings) in January. I said it was too early. I was pleased they were asking, but I need a couple of games."
Chelsea will face London rivals West Ham United in the Premier League on Saturday.