NEW YORK -- Yankees pitcher Luis Severino exited their 7-1 loss to the Chicago White Sox on Friday night with soreness in the back of his right elbow and was diagnosed with a mild right triceps strain following an MRI.
He will go on the 15-day disabled list Saturday. The Yankees say he will not pick up a baseball for five to seven days.
Severino, who has struggled throughout his sophomore season in the big leagues, lasted just 2 2/3 innings against the American League's best team and departed with a team trainer after allowing a two-run home run to Jimmy Rollins that gave the White Sox a 7-1 lead.
Severino was seen shaking out his pitching arm after delivering the home run pitch, a 95 mph fastball that Rollins crushed into the second deck just inside the right-field foul pole. The area of discomfort initially reported by the Yankees is often a sign of a torn ulnar collateral ligament, an injury usually requiring Tommy John surgery.
Yankees manager Joe Girardi said Severino showed no sign of being injured and did not mention any pain before his final pitch. Girardi rejected suggestions that it might have been a pre-existing injury that contributed to Severino's poor start this season.
"I think if it was an ongoing issue, you wouldn't see [pitches in the 97 and 98 mph range]. So I think whatever popped up was new today," Girardi said, speaking before Severino's diagnosis. "But it's a concern. Whenever someone leaves a game because of something in their elbow, you're really concerned. We'll just have to wait and see."
Austin Romine, who caught Severino on Friday night, said he also saw no sign of injury.
"I didn't notice anything," he said. "From my point of view, the ball was coming in good. It came down to execution of pitches. We were just kind of missing."
This was the sixth straight loss for Severino (0-6, 7.46 ERA), who made a splash last season after being recalled from Triple-A at the trade deadline. Last season, Severino was 5-3 with a 2.89 ERA in 11 starts, and he dazzled hitters with a 97 mph fastball and an array of sharp breaking pitches.
He has not been the same pitcher this season, although Girardi said he saw signs that Severino was coming around in his previous outing, a 5-1 loss to the Boston Red Sox in which he allowed three home runs, two of them to David Ortiz.
The White Sox scored three runs off Severino in the second inning Friday night and added four more in the third before he departed with two outs after throwing 81 pitches. But until he left the mound, his velocity seemed consistent with his earlier outings and he showed no sign of being injured.
"I know he's frustrated with where he's at, but I think he's a lot closer, and we're pleased with progress that he's making," Girardi had said before the game. "I saw improvement in his stuff, his slider and changeup, and I thought he located his fastball better the last time. We'd love to see him put it all together."
Severino, 22, has long been considered the top pitching prospect in the Yankees' farm system, and general manager Brian Cashman chose to retain him and the Yankees' other top prospects -- Aaron Judge, Greg Bird and Rob Refsnyder -- at the 2015 trade deadline.
With Severino headed to the DL, it appears Ivan Nova will remain in the rotation when CC Sabathia is eligible to come off the DL at the end of next week. Still, the Yankees will have to find someone to take Severino's turn Wednesday at Arizona.
The Associated Press contributed to this report.