Clemens had his contract selected by the Tigers on Friday.
The move to the 40-man roster protect Clemens from being selected during the upcoming Rule 5 draft. The 25-year-old spent last season at Triple-A Toledo and hit .247/.312/.778 with 18 homers, 59 RBI and 66 runs in 97 games. He figures to be in big-league camp for spring training.