WASHINGTON -- Yankees general manager Brian Cashman took the witness stand Thursday in the federal perjury trial of Roger Clemens, and his testimony provided a preview of how crucial and contentious the appearance of Brian McNamee will be when he sits in the same seat next week.

On direct examination from Assistant U.S. Attorney Steven Durham, Cashman testified about the hiring of McNamee as an assistant strength and conditioning coach specifically to train Clemens after the 1999 season and, eventually, what led to his departure from the Yankees organization at the end of 2001.

The circumstances of McNamee's departure, which included incidents of alleged misbehavior in Florida and Seattle in October 2001, became the initial focus of cross-examination from defense attorney Rusty Hardin, who made it clear he's poised to attack McNamee's credibility and character at every turn.

Although Hardin could not mention that the incident in St. Petersburg, Fla., included an allegation of sexual assault in which McNamee was not charged, he did confirm with Cashman that law enforcement was involved. Cashman also testified to having arrived at McNamee's hotel room in Seattle after Yankees employees were concerned about McNamee's behavior in the hotel lobby, saying McNamee looked "amazed" and "wide-eyed" when Cashman arrived.

Through his cross-examination, Hardin also established that McNamee caused turmoil among Yankees personnel by "always self-promoting" to get more athletes to train with him, prompting a memo to Cashman from head strength coach Jeff Mangold, and overstepping his bounds, such as providing chiropractic adjustments to players and giving pitchers tips to which then-Yankees pitching coach Mel Stottlemyre took exception.

"It was a little more than not playing well in the sandbox, wasn't it?" Hardin asked Cashman, who agreed.

Cashman, the GM for the Yankees since February 1998 who was in that position when Clemens played for the team in 1999-2003 and 2007, is the first Major League Baseball official to testify in the trial of the former star pitcher.

Clemens is being tried on six federal charges of perjury, giving false statements and obstruction of Congress for telling the House Committee on Oversight and Government Reform in 2008 that he never used steroids or human-growth hormone. McNamee, who served as Clemens' strength trainer for nearly a decade, testified before Congress that he injected Clemens with steroids and human-growth hormone, saving in a beer can performance-enhancing drugs, syringes and medical waste the government has introduced as evidence in the trial.

In another development in the case, the Clemens defense team submitted its opposition to the motions by attorneys for both McNamee and his ex-wife to quash a subpoena by Clemens to acquire documents from their divorce proceedings. The subpoena asks for portions of the couple's divorce action that include, among other things, references to Clemens' alleged use of performance-enhancing drugs and the trial itself, references to McNamee's distribution of PEDs, addiction to controlled substances and alcohol and absence from the couple's house where he kept the evidence, as well as criminal conduct and "moral turpitude."

Walton said he will hear the arguments Monday morning in advance of the beginning of the week's trial proceedings, and Durham said he expects McNamee to testify Monday.

Earlier in the day, the jury heard testimony from Dr. David Lintner, the medical director and head team physician for the Astros, who held that position when Clemens played in his hometown of Houston from 2004-06. Lintner testified that he has never administered vitamin B12 shots to athletes, saying, "It doesn't work." He testified that he injected Clemens with the pain medication Toradol in 2005, and explained the use of lidocaine, saying it's basically like novocaine and generally wears off after about two hours.

Lintner also testified that he had not seen syringes of B12 lined up for players to use in a baseball training room, but that he had seen syringes of Toradol lined up for players to use in the training room of the Houston Texans of the National Football League.

Clemens testified before Congress that McNamee injected him with B12 and lidocaine, not performance-enhancing drugs. He also testified that teams regularly would have syringes of B12 lined up ready for injection in the training room.

Dr. Terrence Boos, a chemist for the Drug Enforcement Agency, also returned to the stand for cross-examination and redirect testimony relating to steroids and human-growth hormone, explaining to the jury the different chemical and brand names of steroids that have been at issue in the case.

As Cashman, who told the jury he went to high school and Catholic University in the Washington, D.C., area, began his direct testimony, he told jurors a team's assets are its players. Said Cashman: "I would equate it to if this is a concert then the players are the band and the rest of us are roadies."

With Durham continuing to make things about baseball simple for the jurors, he asked Cashman about the World Series and asked Cashman how many the Yankees had won since he'd been GM. Cashman originally answered five but then interrupted Durham when he realized he'd been mistaken.

"Correction, four -- '98, '99, 2000 and '09," said Cashman, who was assistant GM of the Yankees when they won the World Series in 1996.

Under direct examination from Durham, Cashman made it clear it wasn't his idea to create a special position for McNamee. Cashman said McNamee was hired after Clemens asked for the club to hire McNamee after Game 3 of the American League Championship Series with an injury after allowing five earned runs in just two innings.

"He asked if we would strongly consider hiring him from Toronto the following year so this type of thing wouldn't happen again," said Cashman, who said he asked the late Yankees owner George Steinbrenner for permission to create the position for McNamee and hire him from Toronto.

Asked by Durham if he'd have hired McNamee if it were up to him, Cashman said, "No." Although McNamee's title was assistant strength and conditioning coach, Cashman said, "His duties were to train Roger Clemens."

But Hardin, though a series of questions about internal issues relating to McNamee overstepping the bounds of his job responsibility, had Cashman say that by 2001 McNamee wasn't exclusively Clemens' strength trainer. "Not in the end, no," Cashman said.

Aside from the incidents and insubordination issues that Cashman said led to the Yankees not renewing McNamee's contract after the 2001 season, the cross-examination included that he eventually learned that Yankees trainers in fact did give B12 injections to players, and that several other players such as Derek Jeter and Alex Rodriguez had personal trainers, the way Clemens did with McNamee.

Cashman also summed up why he traded for Clemens in a deal with the Blue Jays prior to the 1999 season, following the Yankees' World Series championship in 1998.

"The biggest thing the New York Yankees could utilize was someone like Roger Clemens," Cashman said. "His reputation was off the charts in terms of work ethic and desire. He was determined to win. He had one more thing to add to his accolades: a World Series."

Cashman also testified that he re-signed Clemens to play for the Yankees in 2007 at age 45 that he needed Clemens' leadership -- "He's one of the rare players I've come across that can lift up a team," Cashman said.

On redirect, Durham asked Cashman about the fact that Clemens came into the season late and had to get back into shape before joining the Yankees.

"Do you know who it was he chose to hire as a strength and conditioning coach?" Durham asked.

"Yes, Brian McNamee," Cashman said.