Even better comparison is Bo Jackson, who actually did go through with re-entering the draft, and went from the Buccaneers to the Raiders.
That said, Elway and Jackson both had legitimate major league baseball aspirations (and Jackson actually followed through on it) to back their leverage up. Crabtree doesn't. Crabtree will straight lose money if he follows through on this proposition. There is absolutely no way to make up the lost money.