Bell looked to injure his foot or ankle just before the end of the third quarter. He limped off the field accompanied by the training staff, who could be seen examining his bare foot on training table.
Reggie Bush will take on a larger share of the carries with Bell sidelined.
Bush is the more dynamic of the two backs, but has been outgained by Bell on Sunday. Bell had nine carries for 49 yards and a touchdown before exiting and added three receptions for 48 yards. Bush had 10 carries for just 26 yards.
Bell had rushed for 277 yards and four touchdowns coming into Sunday's game.
With Matthew Stafford and Calvin Johnson tearing it up through the air, the Lions will likely continue to rely on the passing attack to stay ahead of the Steelers.