The 21-year-old left-back, who is currently recovering from knee surgery, is now out of contract but has been offered a new deal by Warnock.
"There's a deal on the table for Rhoys and I can't imagine him going anywhere else," Warnock told the South London Press.
"His rehab is going well and he's only a couple of weeks away from being back.
"One or two clubs have asked about him on loan and another couple are interested in a permanent deal."
Meanwhile, former Palace striker James Scowcroft, who was released at the end of the season, has joined Leyton Orient.