Manningham hurt the shoulder on the final play of practice on Thursday. He was held out of the team's final workout for Sunday's game against the Philadelphia Eagles as a precaution.
"They thought it was better if he just not work today," coach Tom Coughlin said. "So I'm going to list him as questionable, but hopefully he will make it."
Manningham has started six of seven games this season, catching 28 passes for 439 yards and four touchdowns. If he cannot play, Domenik Hixon or rookie Hakeem Nicks would see more action. Nicks has caught touchdowns in four straight games.
"I'm good. You'll see me out there on Sunday," Manningham said. "I just fell on my shoulder yesterday. I'm cool. I'll be all right."
McKenzie missed last Sunday's game against the Arizona Cardinals with the injury, marking the first time in 38 regular season games that he had been sidelined.
Backup running back Ahmad Bradshaw, who disclosed he has played with a cracked bone in his right foot all season, practiced on a limited basis on Friday and is probable for Sunday's game.
The Giants (5-2) are trying to snap a two-game losing streak.