Star players shouldn't be allowed to play in the preseason. Period. End of discussion.
There's no reason for Aaron Rodgers, Odell Beckham Jr., or Tom Brady to get preseason reps; we know what they can do already; they don't need the reps.
But there are certain players out there who could not only use the reps but who could ultimately earn a roster spot from their preseason play.
If I had the keys to the New York Giants, here's how I'd shape the roster:
Offense
Quarterback:
Eli Manning, Geno Smith, Davis Webb
- Both Josh Johnson and Geno Smith have been "blah" this preseason (neither has thrown a touchdown pass) but Geno has the better track record - at least he was once a semi-productive starting quarterback; Johnson has never been that.