ANN ARBOR, Mich. (AP) — Michigan running game coordinator Mike Hart has returned home after a medical emergency during a game at Indiana led to a hospital stay.

“Things are trending in a positive direction,” the 36-year-old Hart said in a statement released Monday by the football program. “I look forward to rejoining our team soon.”

Coach Jim Harbaugh said Monday that offensive analyst Fred Jackson will fill in for Hart until doctors clear him to return to the staff. The late Gary Moeller hired Jackson in 1992 to coach running backs at Michigan, where he also worked for coaches Lloyd Carr, Rich Rodriguez and Brady Hoke.

Harbaugh said he did not know if Hart will be coaching when the fifth-ranked Wolverines host No. 10 Penn State on Saturday in a game with potential ramifications in the race for a Big Ten title and spot in the College Football Playoff.

It is unclear what happened to Hart, who wound up on the ground late in the first quarter against the Hoosiers. Trainers strapped Hart on a backboard, an ambulance transported him off the field, and he flashed a thumbs-up before going to a nearby hospital for further evaluation.

Hart, who is from Syracuse, New York, is Michigan’s career rushing leader and played for the Indianapolis Colts. He is in his second season on Harbaugh’s staff after coaching running backs at Indiana for four years.