Minutes earlier, four prosecutors representing the US government huddled at their table and then declared: No, they wouldn’t roll the dice to try to introduce new evidence to bolster the credibility of their key witness. There was just too much risk that it could backfire.

The final set of witnesses took the stand Monday as the contentious, start-and-stop Clemens perjury trial entered its ninth week, and both sides played it safe with major decisions. The tenor would have obviously changed completely had the defendant chosen to take the stand, and the jury would have been given another set of dueling impressions of Brian McNamee if the government had sought to bring in more evidence of other players’ use of performance-enhancing drugs.

Clemens is charged with lying to Congress in 2008 when he denied using steroids and human growth hormone in his 24-season major league career. The defense rested, and the government called three rebuttal witnesses Monday - including one who had testy exchanges with a Clemens lawyer about evidence saved with a beer can - and closing arguments are set for Tuesday.

The jury, which has heard from 46 witnesses over 26 days of testimony, could get the case Tuesday afternoon.

McNamee, Clemens’s longtime strength coach, testified he injected Clemens with steroids and HGH. He is the only witness to claim firsthand knowledge of Clemens’s use of performance-enhancing drugs, and Clemens’s lawyers devoted much of the trial attacking his integrity.

To that end, the last of the defense’s 23 witnesses was Jerry Laveroni, the security director for the Yankees when McNamee was the club’s assistant strength and conditioning coach in 2000-01. Clemens lawyer Rusty Hardin used Laveroni to again make mention of two questionable incidents from 2001, when McNamee was involved in a criminal investigation in Florida and appeared disorientated in a hotel room in Seattle during a road trip.

“I don’t believe he could be believed under oath,’’ Laveroni said.

Clemens’s lawyer Rusty Hardin asked how much credibility McNamee has.

“Zero,’’ Laveroni replied.

To counter that powerful statement, the government wanted Laveroni to acknowledge that Yankees players Andy Pettitte, Chuck Knoblauch, and Mike Stanton have all backed up McNamee’s assertion that he helped them get HGH.

However, Hardin said that would allow Laveroni to introduce more details about the Florida and Seattle incidents. The jury, in particular, hasn’t heard that McNamee was questioned about an alleged sexual assault in Florida in connection with a woman who was found to have a date rape drug in her system, or that McNamee then allegedly asked Laveroni to destroy evidence.

The judge said Hardin would be allowed to bring up the Florida incident - just enough to say that McNamee provided false information in connection with the investigation.

That apparently was too much for the quartet of prosecutors, who exchanged whispers and then told the judge they wouldn’t pursue a line of questioning about other players. The cross-examination of Laveroni was very brief - basically long enough for him to acknowledge that Clemens continued to work with McNamee long after 2001.