Gardner, a redshirt junior, is sidelined with what the school initially called a turf toe injury, or sprain of the ligaments around the toe joint. Hoke on Thursday said the injury likely is a slight fracture, according to the Detroit Free Press.
"I think that's what they're worried about, the slight fractures, that kind of stuff," Hoke said, according to the report. "I don't know. They've x-rayed it a couple different times. They MRIed it. It's probably just a little more than just the turf toe."
Morris has appeared in only four games this season. He has completed 5 of 9 passes for 65 yards and accounted for one interception.
"Coming up to last week the chance of me playing became a lot more prominent," Morris said, according to the Free Press. "I prepare for 12 weeks like I would be the starter. They always say you're one play away, well, it's true."
Morris, who finished his high school career as the No. 8 QB in the country, was Hoke's first commit to Michigan after arriving from San Diego State. Morris committed the summer after his sophomore year and quickly began recruiting other players to the Wolverines.
"He's had a really good preparation. We tried to see if Devin (Gardner) could go, and it just wasn't possible," Hoke told the Free Press.
Chantel Jennings of ESPN.com contributed to this report.