SAN FRANCISCO (AP) — Melky Cabrera was suspended 50 games Wednesday following a positive test for testosterone, putting an abrupt end to what had been an MVP-caliber regular season and throwing the San Francisco Giants’ playoff hopes into doubt.

Cabrera leads the National League with 159 hits, and is second in batting average behind Pittsburgh‘s Andrew McCutchen. Cabrera’s penalty was the first for a high-profile player since last year’s NL MVP, Ryan Braun, had his suspension overturned by an arbitrator last winter.

“My positive test was the result of my use of a substance I should not have used,” Cabrera said in a statement released by the union. “I accept my suspension under the Joint Drug Program and I will try to move on with my life. I am deeply sorry for my mistake and I apologize to my teammates, to the San Francisco Giants organization and to the fans for letting them down.”

The suspension would extend into the playoffs if the Giants advance.

Cabrera is batting .346 with 11 home runs and 60 RBIs in his first season with San Francisco and is five hits shy of 1,000 in his big league career. Flashing bright orange spikes, he singled and hit a two-run homer last month in the National League’s 8-0 win in the All-Star game, earning MVP honors for the game and securing homefield advantage for the World Series.