Since when does just playing mean you played well? Rookies are forced into service by 'default' plenty of times. They don't always do well. That's like saying you could be pro bowl safety just because you had to play that position. Doesn't make much sense, does it? Wood, Levitre, Byrd and Nelson did play because they had to, but they did well because they are good players, not because getting the chance to play consitutes good execution.
Also, I don't disagree that Maybin was picked too early, but he still didn't get utilized nearly as much as those other rookies like Byrd, Wood and Levitre.