Cook took five carries for 23 yards and two catches for 14 yards in Saturday's preseason game at Chicago.
Cook had four carries for 18 yards on the opening drive before Damien Harris closed out the series with a two-yard TD on his first touch. Josh Allen and Stefon Diggs were done after that, but most of Buffalo's probable starters played another drive or two, including Cook. Harris then played deep into the second quarter, while 33-year-old Latavius Murray didn't play at all. Regardless of how things break down behind him, Cook should be Buffalo's lead back -- though perhaps as part of a three-man committee -- Week 1 at the Jets on Monday Night Football.