The popular striker has been sidelined for the past eight months with a knee injury picked up in the last game of the 2002/03 season, just weeks after signing a permanent deal with The Lions.
He is scheduled to play the last thirty minutes, alongside another long-term injury victim, Joe Dolan.
"I've been out for a long time and just want to get back into it against Crystal Palace," said McCammon.
"Joe (Dolan) has been out for a year, and he's playing too, which is good.
It has been a really depressing time for me being out injured for so long, but the hunger is there, I just want to get playing again.
"Hopefully I can get a goal or two, show Dennis that my match fitness is there, that I'm hungry to do well and want to play for the club."
Millwall have also announced the departure of Under-19s coach Kevin O'Callaghan. Cally, who broke through from the Lions' youth team in the late 70s, has been a part of Millwall's Youth Academy set up for the past eight years but structural changes with the FA Premier League has meant that his services are no longer required.