The three tailbacks are all averaging 5.2 or 5.3 yards a game but McCalebb has been gobbled up for 44 negative yards in 49 carries.
Big signee Jovon Robinson was ineligible and two-time 1,000-yard rusher Mike Dyer was released from his scholarship after last season.
All the rotating runners might have made it hard for a tailback to get into a rhythm most games.
"We'd like to get a running back into a groove in a game and continue to give him the ball," Chizik said. "We've got a couple of guys that are suited for different things with what we're doing offensively. Some guys are more perimeter guys, some guys are more inside guys.
"We've got to use our personnel to the best of our ability based on what they can do."