Owen Garvan, Gavin Williams and Alan Lee are all back in full training after missing the pre-season tour of Holland and Belgium. Garvan has been out with shingles and tendinitis, the latter a problem which has also beset Williams, while Lee underwent surgery for a groin injury in the summer.
Boss Jim Magilton told the club site: "Owen and Alan have not played any of the pre-season games so far so they are playing catch up.
"But they are making progress and it's a case of getting them match fit now.
"We have to be careful with Owen. He played a lot of games last season for an 18-year-old, so we have to take it one step at a time with him but hopefully he'll be ready for Palace.
"It's the same with Alan. He's had surgery and is behind the others in terms of overall fitness, but he is getting there.
"Gavin played at Boston in our first pre-season friendly and did really well and, although he missed the tour, he should be OK for the start of the season."
The trio are expected to be in the squad for Friday's final pre-season friendly against Lazio (KO 8pm).