Academy defender Chris Casement has signed the two-year contract he was offered earlier in the month. The Northern Ireland U19 international made his debut as a sub at Palace and also came off the bench against Hull on Saturday.
A member of the FA Youth Cup-winning side, the 18-year-old told the club site: "I was going to sign a contract in the summer but the club have brought it forward which is great.
"I'm pleased with the way things are going for me here and breaking into the first team squad and coming on in the last two games has given me a real lift.
"Now I've got to push on from here and make myself a regular in the squad.
"Having so many young players in the squad has helped me settle in. I knew Owen Garvan from playing against him in schoolboy international games and the other lads have been great as well.
"I feel like the 'new boy' in the squad, but if I can play another two or three matches, I think I will start to feel at home."