While still possible, that's very hard to believe. The following is from his profile:
Member of the "All A" Honor Roll at Trinity Presbyterian School ... Earned Academic All-State honors in baseball, basketball and football ... Member of the National Honor Society, Mu Alpha Theta and the National Latin Honor Society ... Won the Harvard and Yale Book Awards ... President of the school's Fellowship of Christian Athletes ... Senior Class Vice President ...
Perhaps he failed Molecular Biology 461! If he did fail a class, I imagine it isn't because an effort wasn't put forth.
From a quick search, McKean was also on the 2006 SEC Freshman Academic Honor Roll and 2008 SEC Academic Honor Roll. These require a GPA of over 3.00. Couldn't find anything on '07.