Pettitte agrees he may have misunderstood Clemens - Article Photos 1/11

Andy Pettitte leaves the Federal Court in Washington, Tuesday, May 1, 2012. Pettitte took the stand Tuesday in the retrial of Roger Clemens on charges that Clemens lied when he told Congress in 2008 that he had never used steroids or human growth hormone. (AP Photo/Manuel Balce Ceneta)