Washington ? Congress wants to be prepared when Roger Clemens and his former trainer, Brian McNamee, head to Capitol Hill.

The House hearing involving Clemens, McNamee and Andy Pettitte was postponed Wednesday from Jan. 16 until Feb. 13, giving lawmakers more time to gather evidence and to coordinate their investigation with the Justice Department.

The House Committee on Oversight and Government Reform was to begin meeting with lawyers for the witnesses Thursday.

Plans are still in place for the Jan. 15 hearing before the same committee about the Mitchell Report on baseball’s Steroids Era. The witnesses that day will be commissioner Bud Selig, union leader Donald Fehr and former Senate majority leader George Mitchell, the report’s author.

Questioned by federal prosecutors last year, McNamee said he injected Clemens with steroids and human growth hormone in 1998, 2000 and 2001. Prosecutors had him repeat those charges to Mitchell, and since the report was issued last month, Clemens has repeatedly and vehemently denied the allegations.

A lawyer for McNamee said Wednesday his client wants immunity from the House committee. McNamee likely will meet today with federal prosecutors.

At the end of last week, Congress asked seven-time Cy Young Award winner Clemens, teammate and friend Pettitte and their ex-trainer, McNamee, to testify under oath. Also invited were former Yankees player Chuck Knoblauch and Kirk Radomski, the former New York Mets clubhouse attendant who was one of the main sources of evidence for the Mitchell Report.