Jason Witten wanted to play DE. CPF told him his future was at TE, but he gave the kid a shot at DE, anyway. Witten was very disappointed when moved to TE. Now he's likely a Hall of Fame TE.
Randall Cobb was determined to play QB in college. CPF was honest with him, said he'd get a chance at QB, but his future was at WR and returning kicks. Cobb went to UK, where he was promised he'd play QB. After a token shot at QB, they moved him to WR and had him returning punts, where he excelled. He's now a star WR in the NFL - just like CPF told him.
Fred Weary came here wanting to play DL. The coaches gave him a shot, then moved him to OL, where he had a nice NFL career.
The moral? 25% of college football players end up playing a different position than they played in high school. Sometimes, a person who's been coaching longer than you've been alive knows a little more than you do about which position you should play.