WASHINGTON — The judge in the Roger Clemens perjury trial is imposing a time limit on all future witnesses in an effort to speed things up.

U.S. District Judge Reggie Walton said today that each side will have no more than 90 minutes to question each witness unless the lawyers can make good cases to show they need an extension.

The limitations were to take effect once Clemens’ chief accuser, Brian McNamee, leaves the stand. McNamee has been testifying all week about the injections he said he gave Clemens more than a decade ago.

The trial is at the end of its fifth week. Walton put the lawyers on notice that if it doesn’t end by June 8, he will have to suspend it for a month because of schedule conflicts.

This is a developing story. An earlier version appears below

WASHINGTON — Brian McNamee testified today that some of the medical evidence he saved in a beer can was not used on former pitcher Roger Clemens.

McNamee is the main prosecution witness in the case against Clemens, who’s accused of lying to Congress when he denied using performance-enhancing drugs. McNamee testified this week that he injected the seven-time Cy Young Award winner with steroids and human growth hormone.

McNamee has said he kept medical evidence from injecting Clemens with steroids in 2001, and stored some of the material in a Miller Lite beer can. But under cross-examination, he acknowledged that some of the items in the can were not in fact used on Clemens, such as a small bottle of HGH, a needle to inject HGH, and a bottle of saline solution used for such injections.

McNamee, Clemens’ former strength and conditioning coach, also testified that a pin included in the beer can might not have been used on Clemens. He said it was either used on Clemens or another player, whom he did not name.

Clemens lawyer Rusty Hardin is trying to raise doubts about the integrity of the evidence.

“You were a police office for three years, you know about chain of custody?” he asked.

“A little bit,” McNamee replied.

“Haven’t you testified that everything in beer can was for Roger?” Hardin asked.

“Not everything,” McNamee said. He added: “I’ve said that all along — it could have been from three different players.”

Although Hardin expressed shock that some items in the beer can were not used on Clemens, McNamee told congressional investigators the same thing in 2008, prior to the hearing in which he and Clemens testified.

An investigator questioned the source of the HGH in the beer can, because McNamee said he injected Clemens with HGH only in 2000, not 2001. The investigator asked if it was Chuck Knoblauch, who has admitted taking HGH.

“It can only be Knoblauch,” McNamee replied.

Also today, U.S. District Judge Reggie Walton said he hoped the trial would be over by June 8. He said he had conflicts for the next several weeks after that and that if the trial isn’t finished by then, “We’ll probably have to go into recess for at least a month, and then we’ll have some real unhappy jurors.”

The day before, out of earshot of the jury, the judged revealing that some jurors had wondered how long the trial will last.

“At this pace, I’ll guess we’ll be here forever,” Walton said.

A prosecutor said he expected to finish the case by the end of next week — or at the latest early the following week. He said the government had 14 more witnesses after McNamee.

“Fourteen additional witnesses?” Walton said incredulously.

After the government’s case, the defense then brings its own witnesses if it chooses to.

Walton said that the case is taking too long, that jurors want to get back to their lives. He warned that one side could suffer — although he didn’t know which one.

Chided by the judge on Thursday for what he called a confusing and mostly pointless cross-examination, Hardin finally turned, after 19 hours, to his central accusation: that McNamee doctored the physical evidence to frame the former star pitcher.

Hardin started that attack late Thursday, insinuating that McNamee manufactured the evidence after Clemens’ televised denials of steroids use.

“All of a sudden, the person being accused is fighting back,” Hardin said, “and you have to figure out some way to save yourself.”

Defense lawyers have said that they will attack the chain of custody of the materials, which McNamee said he stored at his house from 2001 until 2008, when he and his lawyers turned the evidence over to federal authorities.

The Clemens team has also suggested that McNamee put the steroids in the needle after injecting Clemens and that McNamee actually used the needle to inject Clemens with vitamin B12. Clemens has maintained for years that he received B12 shots and the local anesthetic lidocaine but not performance-enhancing drugs.