According to the Los Angeles Times:

Roger Clemens, one of professional baseball's most durable and successful pitchers, is among six players allegedly linked to performance-enhancing drugs by a former teammate, The Times has learned. The names had been blacked out in an affidavit filed in federal court.

Others whose identities had been concealed include Clemens' fellow Houston Astros pitcher Andy Pettitte and former American League most valuable player Miguel Tejada of the Baltimore Orioles. ...

"Jason is loyal to the death, a hardheaded guy who would not give up his friends," one of Grimsley's friends said Saturday. "The only names he discussed with those investigators were names [the investigators] suggested to him."

Via Jim Baumbach.