20 starts is a lot, he had plenty of time.
He looks the part and has decent physical skills, but he is not an NFL quality football player. There is a lot more to it than physical skills when it comes to the NFL, unless you are a complete freak. Instincts, desire, knowledge of the game, being able to understand what's happening on the field while the play is going on all come in to play.
Chad did every thing a lot better than Friel, not just a little better, a lot better. Chad also had the instincts, desire and understanding of the game Friel clearly does not.