It’s rare that a professional athlete ditches his sport in the prime of his career. Pat Tillman did it and became a legend. Ricky Williams did it for a less patriotic yet still fascinating reason. And earlier this week, an excerpt from a soon-to-be-released book authored by his former coach claims that Tiger Woods considered quitting the PGA Tour to become a Navy SEAL.

Today, we’re learning that Peyton Hillis has something in common with Woods by virtue of nearly having something in common with Tillman, Williams and Barry Sanders.

In a report from ESPN’s Adam Schefter that claims Hillis won’t get the franchise tag in Cleveland, Schefter notes that Hillis has “wavered about whether he wants to continue playing football,” adding that he “even considered joining the CIA.”

More from Schefter:

Hillis told Browns coaches as recently as the end of the season that he was contemplating retirement, though it now looks as if he will continue playing, the sources said.

But Hillis has felt defeated throughout his time in football, whether it was being benched at Arkansas in favor of Felix Jones and Darren McFadden, being traded away from the Denver Broncos, or being unable to procure the long-term deal he desired in Cleveland. It led him to tell Cleveland’s coaches that he didn’t know whether he wanted to play football anymore.

OK, I can safely conclude that Hillis just isn’t going to draw a crowd in free agency. The guy has far too many red flags.

First, he’s coming off a terrible season in which he was plagued by injuries. When he was on the field, he averaged just 3.8 yards per carry and scored just three touchdowns.

Second, he’s got some off-field, um, irregularities. Last year we heard that he might have been milking an injury due to his contract status, and now there’s word that Hillis is changing agents for the third time in just over a year.

And third, the guy simply might not be strongly committed to the game of football.

He may be only 26, but in running back years, that’s not young. Hillis will find a home in 2012, but he might not get the deal he wants.

And if that happens, who’s to say he won’t walk away for once and for all?