PHILADELPHIA — In a major break for Bill Cosby, a judge ruled Friday that just one of the comedian’s multitude of other accusers can testify at his trial to bolster charges he drugged and violated a woman more than a decade ago.

The 79-year-old TV star is set to go on trial in June, accused of sexually assaulting former Temple University employee Andrea Constand at his suburban Philadelphia home in 2004. Prosecutors wanted to put 13 more women on the stand to show that his alleged conduct was part of a distinct pattern of behavior.

Judge Steven O’Neill disallowed all but one of those women, saying in a one-page ruling that he carefully weighed the possible value of their testimony against the potential prejudice to Cosby.

The one witness who can testify says the comic drugged and assaulted her in 1996 at a Los Angeles hotel.

Cosby’s lawyer had no immediate comment, but the actor himself re-tweeted news stories on the ruling, adding the hashtags “(hash)KeepWatching” and “(hash)PayAttention.”

The judge’s decision is a setback for prosecutors and means the case will now rest more heavily on Constand’s credibility.

“There is an obvious value to the prosecution when you have numerous accusers. That alone adds tremendous weight to the case,” said lawyer Joseph McGettigan, a prosecutor in the Penn State sex abuse scandal.

The ruling could also shave weeks off the trial.

Cosby, who is free on $1 million bail, could get 10 years in prison if convicted. He is expected in court again Monday to ask that the jurors be selected from another county because of the heavy publicity.