Leonard, who led the NFL in tackles (163) as a rookie in 2018, suffered his concussion in last weekend's victory at Tennessee. He didn't come close to passing the NFL's concussion protocol because he missed the entire week of practice.
Sunday will mark just the second game that Leonard has missed. He missed the Week 5 game at New England last season. Leonard leads the Colts in tackles with 18.
"[Okereke looks] like he needs more playing time. He's that kind of guy," Reich said. "... He'll get some more time this week."