The former head of the New York Yankees' security detail testified Monday that Roger Clemens’s chief accuser has “zero” credibility as the star pitcher’s perjury trial entered its ninth week.

Then, after calling more than 20 witnesses — including the wives of the baseball legend and his former strength coach — the defense team rested its case.

Clemens’s final witness, Jerry Laveroni, the former security chief, told jurors that the ballplayer's former strength coach Brian McNamee should not be trusted. Whether jurors believe McNamee is critical to the prosecution’s case because he is the only witness to testify to firsthand knowledge of Clemens's alleged use of performance-enhancing drugs.

Clemens is charged with perjury, making false statements and obstruction of Congress for denying at a 2008 House hearing that he ever used steroids or human growth hormone.

Laveroni described the friction in the Yankees’ clubhouse between McNamee and the team’s head athletic trainer. But he was not allowed to testify in detail about the basis for his mistrust of McNamee, including the coach’s admitted lies to Florida law enforcement officials in their investigation of an alleged sexual assault.

The defense team also told jurors about the results of a series of drug tests Clemens passed between 2003 and 2007. McNamee testified that he injected the pitcher with the banned substances on several occasions in 1998, 2000 and 2001.

Before turning the case back to prosecutors on Monday, U.S. District Judge Reggie Walton spoke directly to Clemens to ensure that the baseball legend had been given the opportunity to testify on his behalf.

“You’ve discussed this with your lawyers?” Walton asked.

“Yes, judge, I sure have,” said Clemens, who stood at the defense table as he addressed the judge.

Clemens was joined in the courtroom by two of his four sons and his wife, Debbie, who was allowed to observe the trial for the first time after taking the witness stand last week.

Walton expects closing arguments to take place as soon as Tuesday.

Read more: Clemens trial coverage