(Reuters) - Texas Rangers starting pitcher Neftali Feliz will miss the rest of the Major League Baseball (MLB) season and most of next year's campaign to recover from elbow reconstruction surgery, the team said on Tuesday.

The right-hander, who served as the Rangers' closer for the past two seasons before moving into the starting rotation this campaign, has a torn ulnar collateral ligament and will undergo Tommy John elbow reconstruction surgery on Wednesday.

"Fortunately, the nature of the injury, guys do come back from it," Rangers general manger Jon Daniels said in a report on the team's website (texas.rangers.mlb.com).

"The success rate for the surgery is high. He'll get through this and come back. It's an opportunity for him to improve in other areas, but it's going to be a challenge for him."

The news is a blow to the two-time defending American League champion Rangers, who acquired veteran starting pitcher Ryan Dempster in a three-player trade with the Chicago Cubs earlier on Tuesday.

Feliz, a former All-Star and the American League's top rookie in 2010, was 3-1 with a 3.16 earned run average in seven starts and one relief appearance for the Rangers this season but was placed on the disabled list in May because of inflammation in his right elbow.

Despite having their starting rotation hit by injury and inconsistency this season, the Rangers have a 3 1/2-game lead in the American League West division heading into Tuesday's game against the Los Angeles Angels.

(Reporting by Frank Pingue in Toronto; Editing by John O'Brien)