That description of McCoy is so commonplace for white athletes. He's not this, he doesn't have the greatest that. . . then wonderment that the player somehow is as good as he is.
Sporting News has an article on the Tennessee Titans this weekin which Kerry Collins is described as "not having the strongest arm," among other negatives. If he doesn't have the strongest arm in the NFL it's in the upper tier. It's like saying of receivers like, say, Santonio Holmes or Devin Hester, "he's not the fastest receiver in the league," playing down that which is actually a strength.