On Thursday, his replacement took the field hoping to win the job Cook couldn't.
David Fales took snaps with Lions quarterbacks Matthew Stafford and Tom Savage during the Lions' last day of OTAs. Fales' throws didn't look as strong as Stafford's or Savage's, but he completed every ball he threw.
Despite the Lions having a new offense this season — led by new offensive coordinator Darrell Bevell — Fales has to catch up if he hopes to beat out Savage for the backup position. The challenge isn't new to him.