We saw several players last night in the NFL draft that either haven't been starters for long or weren't starters at all and still got drafted in the first round. This is becoming more and more common as NFL GMs adjust to the free agency of today's college football. I think, with all of the tape Casey has produced at this point, the opinion of him as a potential NFL player is pretty set, or close to it. Maybe he transfers and has a breakout year, but he's been very consistent to this point, and his numbers also show that. He's also not some genetic freak that the NFL takes a flier on based on athletic potential. In terms of the NFL, I don't see this transfer helping him, and it may actually hurt him slightly if teams think he just runs from competition.
Now, everything isn't just about the NFL. Playing is its own reward and he certainly has the ability to be the Day 1 starter on many other teams.
In terms of Nebraska, this maybe a good thing. Sims looked like a starting QB in the spring game, which isn't an easy thing to do when everyone is getting used to a new system and the defense decides it still wants to throw half of the kitchen sink at you. Rhule is a pretty straight shooter, and it would be surprising to hear Casey didn't sit down with him and discuss his realistic options.