McCullough incurred the injury during the first half against Miami but remained in the game. The junior has started the season slow, picking up just two tackles in the first two games.
"He'll be close," Zook said. "We'll see."
Should Crum start, it would be the first of the redshirt freshman's career. He has played in both games this season, as he was in for four snaps on defense against Miami.
GAFFNEY TAKES HEAT: Former Florida receiver Jabar Gaffney was thrilled to have three catches for 70 yards in Houston's upset victory at Miami last Sunday. But he was still reeling from the grief he took on Saturday night, when his former team blew a 33-10 lead in the same city.
"I couldn't believe that," Gaffney said. "You've got to drive a stake through their hearts when you've got them down like that. You can't go conservative. [Steve] Spurrier would have put them away."
But while Gaffney may remain partial to his former coach, he clearly has grown beyond his life in Gainesville.
Gaffney and former Miami receiver Andre Johnson have become Texans roommates, close friends and one of the NFL's best young receiving duos.
"Andre gave me the business at the end of that game," Gaffney said.
MEDDER BACK: After dealing with academic issues since Aug. 28, true freshman Carlton Medder returned to practice Wednesday.
Medder, a 6-foot-5, 270-pound defensive end, was not listed on Florida's preseason depth chart.
Zook said he was unsure if Medder would see action any time soon.
The pair graduated high school the same year, as Wynn was named runner-up to Clarett for Mr. Football in Ohio.
"Of course, I still think I was the better running back," Wynn said.
PUTTING ON POUNDS: DE Jarvis Moss, who likely will play Saturday, has put on 20 pounds since the start of camp. At 6-foot-7, the true freshman is up to 231 pounds.
"He's a knuckle dragger," Zook said. "He's got big, long arms. He's going to be able to play."