Could RG3 be Matthew Stafford's backup with Detroit Lions?

In this photo taken Aug. 20, 2015, Washington Redskins quarterback Robert Griffin III (10) passes the ball during the first half of an NFL preseason football game against the Detroit Lions in Landover, Md. Griffin has tweeted what sounded a lot like a goodbye to fans of the Redskins. Griffin wrote Monday: "It was a blessing guys. I just want to say thank you." (AP Photo/Mark Tenally)