Watkins sustained a bruised ribs injury in the Bills' preseason loss to the Steelers on Aug. 16.
The rookie did not play in the Bills' third preseason game on Saturday.
Marrone said he plans to play his starters in the Bills' final preseason game on Thursday night.
The Bills traded up to select Watkins with the No. 4 pick in the 2014 NFL draft. Buffalo sent its 2014 first-round pick, 2015 fourth-round pick and 2015 first-round pick to Cleveland in the trade.
- Sarah Barshop