This is somewhat unfair because there are dozens and dozens of other factors at play here besides QB play, but I thought this was interesting nonetheless. This examines how the college teams of current rookie QBs have done this season without them.
college teams that got worse
North Carolina with Mitchell Trubisky: 8-5
North Carolina after Mitchell Trubisky: 3-8
Pittsburgh with Nathan Peterman: 8-5
Pittsburgh after Nathan Peterman: 4-7
college teams that stayed about the same
Clemson with Deshaun Watson: 14-1
Clemson after Deshaun Watson: 10-1
Texas Tech with Pat Mahomes: 5-7
Texas Tech after Pat Mahomes: 5-6
Iowa with C.J. Beathard: 8-5
Iowa after C.J. Beathard: 6-5
college teams that got better
Notre Dame with DeShone Kizer: 4-8
Notre Dame after DeShone Kizer: 9-2