An MRI on LSU reliever Alden Cartwright’s right arm Tuesday revealed a 100 percent tear of his ulnar collateral ligament and the Baton Rouge native will require Tommy John surgery, coach Paul Mainieri said.

Cartwright exited Sunday’s 10-5 win against Auburn, where he said he “felt a pop” in his elbow after throwing his fourth pitch, which bounced in the dirt and had Cartwright immediately crouching in pain.

He will undergo surgery next Wednesday, April 13, Mainieri said.

Cartwright told Mainieri of the diagnosis in Mainieri’s office.

“All I could do was hug him and tell him how sorry I was for his sake,” Mainieri said after the Tigers’ 11-1 victory against Southern on Tuesday night at Alex Box Stadium. “Alden has a very positive attitude. ... His career’s not over. He’ll still be able to contribute to LSU baseball, but everything will just be delayed a little bit.”

Rehabilitation from Tommy John surgery customarily takes a full year, putting Cartwright’s 2016 season in peril. He qualifies for a medical redshirt, though LSU will have to formally request one for him after the season.

Cartwright walked out to short right field Tuesday afternoon to deliver the news to pitching coach Alan Dunn, who embraced his junior right-hander that had a 2.32 ERA and 13 strikeouts in 11 appearances spanning 15.1 innings.

A versatile, veteran arm out of the bullpen, Cartwright made two midweek starts and was inserted into a bevy of tight situations — his last, perhaps, being the biggest.

Mainieri entrusted him Sunday with the bases loaded, one out and a tenuous 6-4 lead before the injury occurred.

“I kind of knew it was coming,” Cartwright said of the diagnosis. “I knew in Auburn that it popped. I knew it wasn’t good and (the doctor) knew before the MRI it wasn’t going to be good. ...

“The only thing I don’t get to do, I don’t get to go on the road. But I still get to go to all the home games, dress out like that and motivate my teammates the best I could.”

De la Torre back in Jaguars lineup

Southern senior catcher Jose de la Torre was back in the lineup in his customary No. 3 spot in the batting order after missing the past four games.

De la Torre returned home to Puerto Rico to attend to a personal matter and missed an 18-2 loss at Southeastern last Tuesday and a three-game sweep at the hands of Texas Southern over the weekend.

He entered the game tied for the team lead in batting average (.359) and home runs (two) and leading in runs batted in (17). De la Torre went 0-for-3 with a walk and committed two throwing errors.

Gales throws first pitch

Southern wide receiver Devon Gales took part in the ceremonial first-pitch before the game.

Gales, a sophomore from Baton Rouge, suffered a severe spinal injury in loss at Georgia last September.

He underwent surgery in Athens, Georgia, and spent five months rehabbing in Atlanta before returning home recently.

Gales received a standing ovation as he threw his first pitch from his wheelchair to Tigers pitcher Jared Poché.

Cador shows patience

When Southern starter Harold Myles got off to a slow start against Southeastern in his last start a week earlier,

Jaguars coach Roger Cador had little patience. Myles hit the leadoff batter, gave up a single to the next batter and fell behind the third batter 2-0 before Cador took him out, saying he didn’t like his “body language.”

Myles got off to a slow start again Tuesday, but Cador was much more patient. The sophomore right-hander gave up four runs on three singles, two walks and two hit batsmen and still had the bases loaded with two out in the first before Cador sent Justin Freeman to the bullpen to warm up.

Pitching coach Dan Canevari visited the mound and Myles got Antoine Duplantis, the 10th batter in the inning on a grounder to second for the third out.

“He was overthrowing,” Cador said. “I was hoping that he would stop overthrowing — and he did that in the second inning — because he was the one guy who could keep the ball in the park because of his sinker. It’s tough to lift that ball out of the park. He proved that by breezing through the next three innings.”

Myles (0-5) shut out the Tigers in the second, third and fourth innings before allowing three runs in the fifth, his final inning.

Follow Chandler Rome on Twitter, @Chandler_Rome.