Hunter has been on the physically unable to perform list since tearing his ACL in May.
Chargers head coach Anthony Lynn told ESPN's Josina Anderson that Henry is close to being able to return, but the team decided against activating him for Sunday's game.
If the Chargers win on Sunday, they must decide by Monday whether to activate him, or he will not be able to play for the rest of the playoffs.
Henry finished third on the Chargers in receptions (45) and receiving yards (579) last season. He also had four touchdown receptions.