Roger Clemens' former personal trainer, Brian McNamee, has served the former Major League pitcher with a summons that says McNamee reserves the right to sue Clemens for defamation, the New York Daily News reported Friday.

According to the Daily News, representatives of McNamee's lawyers served Clemens with the summons last week in Houston.

The newspaper wrote that any defamation complaint filed by McNamee would be based on public comments Clemens made in reference to McNamee challenging Clemens' truthfulness. Such comments were made by Clemens in a 2008 interview on "60 Minutes" and to a congressional committee investigating the Mitchell Report on steroid use in baseball in which McNamee said he injected Clemens with steroids and human growth hormone. Clemens has already filed a defamation suit against McNamee.

"It is a suit for damages to Brian, based on allegations Clemens made to Congress and in the press," Earl Ward, one of McNamee's lawyers, told the Daily News.

Of last week's summons, the Daily News wrote, "The 'endorsed summons' officially notifies Clemens of a complaint McNamee's attorneys quietly filed in a Queens courthouse in December, preserving McNamee's right to sue Clemens within a statute of limitations."