Gates has been dealing with a painful tear of the plantar fascia in his right foot and wasn't expected to play in Sunday's game at Denver. The Chargers were eliminated from playoff contention in last Sunday's 34-20 loss at Cincinnati.
Gates hasn't played since a Dec. 5 loss to Oakland. He has 50 passes for a team-high 782 yards and 10 touchdowns in 10 games.
Latsko spent most of the last three seasons on the practice squad with Carolina and San Diego. The Chargers signed him to the active roster for seven games in 2008 but he has yet to play his first NFL snap.