Well, I have seen him play.
He's not going to be a QB in the NFL and have success. Period. JaMarcus Russell had a better shot at being successful than Tebow in the pros, he at least had the correct throwing motion. He did, however lack anything like the brain required, and his work ethic was unbelievably bad.
Pilgrim's comment about him being a "top 10 QB the day he steps on the field" is one of the most hilarious things I've ever read here.
The dude is a good, probably great, athlete. He does not possess what is necessary to work as a QB in a pro-style NFL offense, wrong mechanics, wrong everything.
If Denver has any sense, they'll make an H-back out of him, and occasionally run some kind of wildcat formation with him. He had great physical skills, and a lot of heart, with a real strong work ethic. If he puts his mind to being a successful NFL player, at whatever position the team feels he is suited for, he will do fine.
If they try to force his square peg into a round hole and make an actual full time QB out of him, they will be teaching a pig to sing.