Gary Cahill believes Chelsea will have to steer clear of injury problems if they are to defend their Premier League title.
Eden Hazard and Tiemoue Bakayoko are set to miss the season opener at home to Burnley on Saturday, while new arrivals Antonio Rudiger and Alvaro Morata are short of match fitness.
With Chelsea having more than 20 players out on loan and the likes of Nemanja Matic, Nathan Ake, Asmir Begovic and Juan Cuadrado having left on a permanent basis, Antonio Conte's squad looks thin.
And Cahill claims the squad lists for the Community Shield fixture against Arsenal on Sunday demonstrated Chelsea's lack of depth.
"The back of the programme was interesting," the Chelsea captain told reporters. "In terms of quality we've certainly got that, but you have to hope we don't have too many injuries.
"Obviously the new players who have just come, they're going to be vitally important. There's no doubt we've added quality to the team.
"But with playing more games due to the Champions League this season, the numbers are going to be tested. We just have to keep everybody fit and sharp. Rest is going to be important because we're going to have a lot of games.
"As players we are in control of what we do and the way we prepare for the games. The other stuff outside of that [transfers] is none of our business."
After a 1-1 draw at Wembley, Chelsea were defeated 4-1 by Arsenal on penalties as the new 'ABBA' shoot-out system was trialled.
Cahill was the only Chelsea player to score his kick as Morata hit the outside of the post and goalkeeper Thibaut Courtois sent his bizarre effort flying over the crossbar, with the England international unimpressed with the change from the standard 'ABAB' order.
"First impression, I'm not a fan," Cahill said. "We were a couple of goals down after one penalty, so mentally that's different than when you've got one, one, one, one.
"I went and then obviously 2-1 or 3-1 down or whatever, mentally it's different, so I'm not a fan. Obviously we won the toss and I asked the team, to see what everyone wanted to do. We wanted to go first so we went first.
"The mood in the camp is fine. The Community Shield is not a setback but I do see it as a disappointment. It is hurtful because we lost a game we wanted to win and had a chance to win a trophy. We need to brush that off and prepare for an important season."