(Reuters) - Philadelphia Phillies infielder Freddy Galvis has been suspended for 50 games by Major League Baseball after he tested positive for a performance enhancing substance, the league commissioner said on Tuesday.

The 22-year-old rookie Galvis, who has denied any wrong doing, is on the disabled list with a fractured back but the penalty will still begin immediately.

"I have not and never would knowingly use anything illegal to enhance my performance," Galvis said in a statement on the team website (philadelphia.phillies.mlb.com). "I have always tried to follow the team's strength and conditioning methods, listen to the trainers, work out hard and eat right.

"Unfortunately, the rules are the rules, and I will be suspended."

Galvis is batting .226 with 15 doubles and 24 RBIs while helping to fill in for the injured Chase Utley.

The Phillies have expressed their support for Galvis while accepting the suspension.

Philadelphia (32-37) are last in the National League East after winning the previous five division titles.

(Writing by Jahmal Corner in Los Angeles; Editing by Greg Stutchbury)