The NCAA is investigating Johnny Manziel, the Texas A&M Heisman Trophy winner, for accepting "a five-figure flat fee" for signing photos and memorabilia, ESPN reported Sunday.

The network cited anonymous sources who witnessed the January 2013 signings that took place in South Florida but did not see the cash exchange. It also noted that online sales of signed Manzielphotos show a lot of 999 sequentially numbered items. Industry insiders said that is a sign they were done in large bunches, and not just fans reselling items they coincidentally had the redshirt sophomore quarterback autograph. 

The investigation began in June and whether the NCAA can verify the charge remains to be seen. Unnamed sources rarely cooperate with NCAA investigators, although the Association would have the ability to review all of Manziel's bank records where, even for a person from a family of means, a large sum of money (if deposited in a bank account) might stick out.

Based on past case precedent – which, when dealing with the inconsistent NCAA, could mean nothing – Manziel could be facing a five-game suspension if found guilty. That was the penalty given to a number of Ohio State players who exchanged memorabilia for tattoos and other gifts under the same NCAA rule in 2011.

Manziel's Aggies host No. 1 Alabama on Sept. 14, the third game of their season. It is the single-most anticipated contest of the college football season and perhaps the biggest in school history.

Unlike Ohio State, the Texas A&M program isn't under any threat of sanction unless it is determined a coach or administrator at the school knew of the alleged deal. Former Buckeyes coach Jim Tressel did know of his players dealing memorabilia and (perhaps opposed to the rule) chose to play them for an entire season anyway. That cost him his job and the Buckeyes a bowl game following the 2012 season.

The investigation into Manziel is bigger than just the particulars of the latest NCAA cops and robbers case, however.

It shines an even brighter spotlight on the NCAA's system of "amateurism" that is under significant attack both legally and politically.

The NCAA is the last major athletic organization to attempt to keep its adult athletes from being paid or profiting off their own fame and accomplishment.

It wants all revenue to come into its coffers and its coffers only – jerseys and T-shirts with Manziel's numbers are huge sellers, autographed helmets can be purchased through the university and a table with Manziel and fellow Heisman winner John David Crow at a school banquet was recently sold for $20,000.

Even the ethically challenged International Olympic Committee bailed on the questionable policy back in the 1980s and allowed athletes to be paid for endorsements, memorabilia deals and other business opportunities.

 Although hardliners had predicted the practice would adversely affect the athletes or the popularity of the Olympics, allowing Usain Bolt and Michael Phelps to sell shoes and sandwiches benefited everyone. Athletes, especially in developing nations, stopped being forced to live in poverty. And the Games might now be as popular as ever.

It's the so-called "Olympic Model" and it's the soundest one for the NCAA to embrace as the drumbeat for better compensation for student-athletes increases.

Read more from Yahoo! Sports