Clemens, 50, has signed with the Sugar Land (Texas) Skeeters of the independent Atlantic League and is slated to start on Saturday against the Bridgeport Bluefish.
"Guys love to play; it's in our blood," Yankees manager Joe Girardi said. "If he still feels he can play and pitch and enjoys it -- I know it's not at the big league level, but God bless him."
Girardi and Clemens were teammates on the World Series-winning 1999 Yankees. Clemens finished his big league career with the 2007 Bombers and was acquitted in June of charges that he lied to Congress when he denied using performance-enhancing drugs.