Quarterback Cody Kessler, who was 0-5 as a starter, remains in the NFL's concussion protocol and has been ruled out. The other quarterbacks on the roster are rookies Kevin Hogan and Joe Callahan. With Kessler sidelined, Hogan will be the backup.
McCown's return comes after he suffered a broken left collarbone against the Baltimore Ravens on Sept. 18 in his only game this season. He was medically cleared Wednesday and practiced fully for the first time since the injury. He had been doing limited work in practice the previous two weeks.
"He just likes to play," Jackson said Friday of McCown. "Anytime you're a veteran player and playing as long as he has, you're excited about having the opportunity to go back out there with your teammates.
"The last time he played, we had a great chance to win the game and then obviously he got hurt. But he showed tremendous poise and toughness and played through the game. Hopefully we'll go out and protect him and give him a chance to lead this team."