Roger Clemens faces down his trainer, and Congress

Roger Clemens is no stranger to showdowns. Every time he steps on the pitcher's mound, it's a showdown against the batter.

Former New York Yankees pitcher Roger Clemens on Capitol Hill in Washington

But today, Clemens is in a vastly different, incredibly risky showdown. He will sit near the man who says he injected Clemens with steroids and human growth hormones, and Clemens will declare under oath that it's all a lie.

His former trainer, Brian McNamee, will testify before the House Committee on Oversight and Government Reform that he injected Clemens 16 times in 1998, 2000, and 2001 with steroids and Human Growth Hormone, or HGH.

At least one of these men must be an out-and-out liar, will likely perjure himself, and could end up in prison because of it.

Clemens was mentioned 82 times in former Senator George Mitchell's steroid report that came out of a two year investigation. If he is to come out on top, he will have to convince Congressmen that not only is his former trainer a liar, but that Senator Mitchell was gullible and sloppy in his report.

Clemens will also likely be contradicting testimony from former teammate and good friend Andy Pettitte, who has acknowledged being injected by McNamee.

Clemens faces an uphill battle, one that can't be won with a great fastball.

– Gary Tuchman, 360° Correspondent