Palmer made his first Stamford Bridge start since the Crystal Palace game in Chelsea’s 2-0 win over Everton at the weekend.
The England star admitted he was “nowhere near 100 per cent in terms of fitness” after getting back on the scoresheet for the Blues at Stamford Bridge as he slowly gets back to full fitness.
The 23-year-old has started just four Premier League games this season due to groin and toe injuries, which forced him to miss more than two months of fixtures for the side.
Now, Maresca has given an honest assessment of the midfielder as his side prepares to face League One side Cardiff in the EFL Cup.
“I already said many times, Cole is one of the players that deserves to be protected. He is not available to play two games in three days.”
England manager Thomas Tuchel will be keeping a close eye on Palmer ahead of his World Cup team selection next year, which the Chelsea star could be a part of if he gets back to full form over the next few months.
Palmer told BBC Sport: "I wouldn't say I'm at my best yet. I'm still dealing with an injury. Hopefully it gets better and better, but there's still a bit to go.
"It is getting better. The stuff I've been doing with the physios at the club. It's just a matter of not doing too much too soon.
"Literally, it's just a day-by-day thing. Hopefully it gets better."