(Reuters) - Former Cy Young winner Chris Carpenter will likely miss the 2013 Major League Baseball campaign due to a nagging shoulder injury that kept him out most of last season, the St. Louis Cardinals said on Tuesday.

Carpenter told team officials last week that he was still experiencing discomfort and numbness in his right shoulder, according to Cardinals General Manager John Mozeliak.

"Do I envision Carp returning? I would say it's very unlikely, so no," Mozeliak said during a news conference at Busch Stadium in St. Louis a week before the Cardinals hold their first spring training workout.

A three-time All-Star with a 144-94 career record since his MLB debut in 1997, Carpenter won the Cy Young Award in 2005 as the National League's top pitcher and has won two World Series titles with the Cardinals.

Carpenter, who turns 38 in April, was shut down two weeks into spring training last year due to his shoulder problems and did not pitch until the end of the season when he made three starts, going 0-2.

The right-hander beat the Washington Nationals to go 1-0 during the Cardinals' victory in the National League Division Series, but went 0-2 as St. Louis fell to eventual World Series champion San Francisco Giants in the League Championship Series.

Only weeks ago, Carpenter had told reporters he was feeling good and looking forward to an early start at spring training before suffering a setback.

"On Friday he had notified me ... he is still feeling the same discomfort he was experiencing during last year's season and just felt like at this point he can no longer continue to try to throw," Mozeliak said.

"He was sad. He was definitely teary-eyed and I think he felt like, to some degree, he was letting us down."

A first-round draft pick by the Toronto Blue Jays in 1993, Carpenter has been slowed by injuries throughout his career. He has landed on the disabled list 11 times and has undergone separate surgeries on both his right shoulder and right elbow.

"When I look back at his career, the one thing about him is he's probably one of the most competitive players I've ever been around and truly willed himself to win," Mozeliak said.

"If you think about all the injuries he went through in his career and how he willed his way back to the field, I've always admired that about him."

(Reporting by Larry Fine in New York; Editing by Frank Pingue)