McNamee, a former strength coach for the Blue Jays and Yankees, told Mitchell he personally injected Clemens with steroids in 1998 while they were with Toronto, and with steroids and human growth hormone in 2000 and 2001 while with New York.
"Roger took bunches of his shots over his career, much the way racehorses do, unfortunately," Clemens' lawyer, Rusty Hardin, said after the excepts were released Thursday.
Clemens issued a video statement on Dec. 23 denying McNamee's accusations and plans to hold a news conference Monday. Clemens did not mention injections of painkillers or vitamins.
"That short statement didn't go into any details and simply told the public at large he did not take steroids or any other performance-enhancing drugs. That's never been a contention of his," Hardin said.
"The reason he hasn't stepped out personally before now was really our decision, not his, and that was to more deliberately look into how in the world the Mitchell report could have reached what we believe was this totally wrong conclusion before we started talking out. Now we're more comfortable with all of that, and he's going to answer whatever questions they have."
During the CBS interview, recorded last Friday at Clemens' home in Katy, Texas, Clemens was asked whether McNamee had injected him with any drugs.
"Lidocaine and B-12," Clemens responded. "It's for my joints, and B-12 I still take today."
Lidocaine is a local anesthetic that can be used by dentists and in minor surgery. It also is available as part of ointments used to treat skin inflammation.
Clemens told CBS that McNamee's accusation was "ridiculous" and said he "never" used banned substances.
"Swear?" CBS's Mike Wallace asked Clemens.
"Swear," Clemens responded.
Baseball players and owners did not have an agreement to ban steroids until September 2002, and they didn't ban HGH until January 2005.
The Mitchell report states McNamee injected Clemens with substances provided by the pitcher or that McNamee obtained from former Mets clubhouse attendant Kirk Radomski. In his video statement, Clemens said: "I did not provide Brian McNamee with any drugs to inject into my body. Brian McNamee did not inject steroids or human growth hormones into my body."
McNamee's lawyer, Richard Emery, has threatened to sue the seven-time Cy Young Award winner for defamation.
"I think that this is a lawyers' game, which allows him to try and attempt to say that McNamee didn't know what he was injecting or that at least Clemens didn't know what he was injecting," Emery said.
"It really depends now on how the whole interview goes, and whether he goes after Brian. Look, I don't care whether Clemens used Sodium Pentothal. I don't care if he used strontium 90. My only concern is for Brian's well-being and his future."
Emery said a decision whether to sue won't be made until after the "60 Minutes" interview is broadcast.
"It really depends on what a reasonable person would take away from the entire interview as to whether he's going to damage Brian. And we can't tell until what we see happens on Sunday," Emery said. "But it is fascinating. I think that Hardin and Clemens are responding to the fact that McNamee is going to defend himself aggressively by them trying to parse this closely and issue this statement through CBS. So it's fascinating, and I'm glad to see that they are responding to Brian's notice to them that he is not going to be trashed by them."
When Baltimore's Rafael Palmeiro tested positive for steroids in 2005 and was suspended for 10 days, he said a tainted vial of B-12 given to him by a teammate -- later identified as Miguel Tejada -- might have caused the doping violation.
Emery wouldn't say whether McNamee did inject Clemens with lidocaine and B-12.
"That's much too specific. That evidence has yet to be developed," he said. "There is a ton of evidence that the Mitchell report failed to explore that will corroborate Brian, and so it would be foolhardy for Clemens or Hardin to allow Clemens to trash Brian."
Emery said it was unlikely McNamee would sue CBS. He also hasn't decided whether a suit would be filed in New York state court or federal court.
"Either court in New York would be perfectly acceptable," he said. "No New York jury is going to be hoodwinked by this claim if he ends up defaming Brian."
Mets first baseman Carlos Delgado, a teammate of Clemens on the 1998 Blue Jays, said the pitcher and strength coach didn't appear to be close at the time.
"It wasn't anything more than the usual pitcher and conditioning relationship," he said.
Delgado did find fault with Mitchell's report.
"There's a lot of accusations with not enough evidence," he said.