I'm actually disagreeing just a little bit.
I'll get absolutely torched for saying this, but it's fact...
There's no such thing as a white cornerback in the NFL and Riley knows it. Hasn't been a regular starter since Sehorn 20 years ago. His best option would be to add about 10 lbs and take on a Harrison Smith type role playing safety. I'd bet dollars for donuts that he knows his only viable shot is to put a little size on and try to latch on somewhere as a safety, otherwise he's going to be a career special teamer, and maybe he's ok with that.
The other scenario might be that he knows it's more likely to win the lottery than play CB in the NFL, and so he wants another ride with his teammates.