ah, the battle of Clemens vs McNamee. He said vs He said. and now a possibility of physical evidence.
Rationally speaking, McNamee has everything to lose by not telling the truth and it would make sense that he covered his ass (and parts of Rogers' in 2000-2001...) when he was injecting PED. It's only a matter of time before Clemens' pleads guilty, but not admitting to fault.
We see this "change of heart" all the time--Michael Vick, Marion Jones, soon it will be Barry Bonds and Roger Clemens. and it's only because they know they are going to lose big time, really big. But when it happens, all the damages are already done and no fan will believe in you again!
The winner of this so far is Andy Pettitte, who came out clean without denying the Mitchell Report first.
the message is, of course: have true sportsmanship. If you lose, lose gracefully. If you win, win gracefully.