McGee will miss his second consecutive game because of a left knee sprained in Buffalo's win at St. Louis last month. Rookie Leodis McKelvin will start in McGee's place.
Schobel didn't practice all week and has been wearing a protective boot on his left foot to help heal a ligament and bone injury. He aggravated the injury against the Cardinals on Oct. 5, making him more likely to also miss Sunday's game.
Fowler didn't practice for the second straight day, while Youboty was limited on Friday.
The AFC East-leading Bills (4-1) have a chance to go 5-1 for the first time since 1995, while the 3-3 Chargers have won three of their last four after an 0-2 start.