Roger Clemens unleashed the equivalent of a verbal fastball on Tuesday when he forcefully denied allegations by his former personal trainer that he used steroids and human growth hormone.

In George J. Mitchell’s report on the use of performance-enhancing drugs in baseball, Mitchell said that Clemens’s trainer, Brian McNamee, said that he had injected Clemens with illegal drugs at least 16 times while Clemens was pitching for the Toronto Blue Jays in 1998, and then with the Yankees in 2000 and 2001.

Clemens’s lawyer, Rusty Hardin, said that his client had never used steroids when the report was released last Thursday. This time, Clemens said it himself in a statement released through Randy Hendricks, one of his agents.

“I want to state clearly and without qualification: I did not take steroids, human growth hormone or any other banned substances at any time in my baseball career or, in fact, my entire life,” Clemens said.

“Those substances represent a dangerous and destructive shortcut that no athlete should ever take.”McNamee, who remained Clemens’s personal trainer through the 2007 season, signed a proffer agreement with federal prosecutors before speaking to Mitchell who conducted a 20-month investigation of performance-enhancing drugs in baseball. Several former prosecutors said that agreement adds credibility to McNamee’s testimony because of the severe penalties he could have faced if he had lied. Still, Clemens insisted he has been drug-free during his career in which he won 354 games.

“I am disappointed that my 25 years in public life have apparently not earned me the benefit of the doubt, but I understand that Senator Mitchell’s report has raised many serious questions,” Clemens said. “I plan to publicly answer all of those questions at the appropriate time in the appropriate way. I only ask that in the meantime, people not rush to judgment.”

Andy Pettitte of the Yankees, who is Clemens’s close friend and who also used McNamee as a trainer, admitted last Saturday that he had used human growth hormone twice during the 2002 season. McNamee told Mitchell that Pettitte asked him about human growth hormone during the 2001 season, but McNamee discouraged it. One year later, Pettitte, who was rehabilitating from an elbow injury, had McNamee meet him in Tampa, Fla., and inject him with human growth hormone.