As if the frustration from the Roger Clemens perjury trial had not built up enough already, now the main witness and only one who claims to have direct knowledge of the former Major League superstar pitcher's steroid use is telling the court that his memories of said events have 'evolved' over the years.

That's right. Former strength trainer Brian McNamee, billed as a liar by his harshest critics, turns out to have an evolving memory almost a month into the second attempt by the government to convict Clemens of perjury.

After everything bizarre that's happened in this trial, from evidence being presented out of a Miller Lite Can, to jurors being dismissed for sleeping through the (high-profile) court proceedings, now McNamee has admitted that some of the evidence from the beer can, including the needle there, was not used on Clemens.

From reading tweets from Associated Press writer Joseph White, Clemens' lawyers picked McNamee apart and portrayed him as the serial liar they always have.

#Clemens lawyer hammered away at McNamee, aiming for a "gotcha" moment over the famous beer can evidence. McNamee conceded he "misspoke."

— Joseph White Jr. (@JGWhiteAP) May 18, 2012

At one point McNamee hung his head while on the stand. Not a pretty sight. #clemens

— Joseph White Jr. (@JGWhiteAP) May 18, 2012

At another point, a juror gave McNamee a tissue. Didn't know that was allowed. The judge didn't see it. #clemens

— Joseph White Jr. (@JGWhiteAP) May 18, 2012

#Clemens lawyer also made a big deal of McNamee's 2 DUI convictions. Took McNamee about 5 minutes to explain one of them.

— Joseph White Jr. (@JGWhiteAP) May 18, 2012

Due to McNamee's testimony, and Andy Pettitte's too for that matter, Clemens is likely to beat this thing for a second time in less than a year's span, with a lot of tax dollars in the wind behind it.

Read more about the Roger Clemens trial at our StoryStream here.