Imagine a hypothetical world where suddenly college athletes are able to sign endorsement deals while maintaining their eligibility.

How much could a star like Heisman Trophy winner Johnny Manziel make?

According to several marketing experts, the value even for a player as dynamic and well-known as Manziel would not rival that of pro stars. They say the biggest drawback is that even if the NCAA rules ever changed, the athletes would still have to deal with fans' perception that college is different from the pros.

Manziel himself acknowledged the same challenges when asked what a player would do if faced with that option.

The Texas A&M quarterback says: "I think it's a tough situation, and that's why it's how it is today."