Yankees third baseman Miguel Andujar, the runner-up in voting for the American League Rookie of the Year Award last season, has decided to have season-ending surgery, after nearly six weeks of trying to rehabilitate and then to play through a torn labrum in his throwing shoulder.Chris Ahmad, the Yankees\u2019 head physician, will perform the surgery on Andujar, 24, on Monday at NewYork-Presbyterian Hospital, the team announced Wednesday night.\u201cMiguel tried to give as much to the team as he could but realized that he just wasn\u2019t physically able to deal with the pain and still be as productive as we all know he can be,\u201d Andujar\u2019s agent, Ulises Cabrera, said in a text message after the team\u2019s announcement.In a Yankees season defined by injuries \u2014 and by a 26-16 record in spite of them \u2014 Andujar became their first player to be shut down completely. Seventeen Yankees have hit the injured list in the first quarter of the season, and a major-league-leading 13 are currently there.\u201cMiggy is beloved in that room and obviously really important to us between the lines and just who he is,\u201d Yankees Manager Aaron Boone said. \u201cHopefully this is a really good step for him in starting the healing process, so look forward to him getting it done and on his way back and making a full recovery.\u201dAndujar, who hit .297 with 27 home runs and 92 runs batted in last season, originally hurt his right shoulder diving back to third base on a pickoff attempt on March 31. After a magnetic resonance imaging examination, the Yankees said that the tear was small and that Andujar\u2019s shoulder still appeared to have substantial strength.He received a couple of medical opinions in which surgery was not suggested, Boone said earlier this week.The injury interfered mostly with Andujar\u2019s throwing, not his hitting, and the Yankees put him through a stretching and strengthening routine, plus a gradual throwing program, before he returned from the injured list on May 4.Andujar played in nine games after he came back, mostly as the designated hitter, while Gio Urshela, a sure-handed fielder, took over at third base. But Andujar\u2019s performance at the plate caused concern.Usually a stout hitter, he was 3 for 34 with no runs batted in after his return. He struck out nine times and was making weaker contact than usual. He batted .128 over all in 12 games this season.On Monday the Yankees decided to put Andujar back on the I.L. and to reconsider the options.Andujar recently had another M.R.I. exam, and the results were nearly identical to the previous one, Boone said Tuesday. Andujar was then given a few days to discuss the next move with his family and confidantes. He told the team on Wednesday that he would have the operation.\u201cIt\u2019s sad,\u201d Urshela said, adding later, \u201cI\u2019ll pray for him to get a quick recovery and get back soon.\u201dCabrera commended the Yankees\u2019 treatment of Andujar throughout the process. He said that both doctors involved in the case \u2014 Ahmad and David Altchek, who provided a second opinion \u2014 were confident that Andujar could return to his previous form.After struggling in the field last season \u2014 only three major league third basemen made more errors than his 15 \u2014 Andujar spent the off-season and spring training working on his fielding and throwing, which he often preferred to do from a sidearm angle rather than the traditional overhand method.In his absence, Urshela has thrived, and over the weekend, the Yankees claimed infielder Breyvic Valera, who has played in parts of two major league seasons, off waivers from the San Francisco Giants. Valera was sent to Class AAA Scranton\/Wilkes-Barre, where he and Tyler Wade can serve as infield insurance.On Tuesday night, the Yankees traded for Kendrys Morales, who Boone said was expected to get quite a few at-bats as the designated hitter. Morales, 35, was recently designated for assignment by the Oakland Athletics after hitting .204 with a .569 on-base-plus-slugging percentage.He went 1 for 2 with two walks in his Yankees\u2019 debut, in the nightcap of their doubleheader sweep against the Baltimore Orioles on Wednesday.But advanced metrics suggest that Morales was hitting the ball harder than his statistics showed. Last season with the Toronto Blue Jays, Morales hit .249 with 21 home runs and a .769 O.P.S. Morales, a switch hitter, has played in parts of 13 major league seasons, most with the Los Angeles Angels, and is a career .267 hitter with 212 home runs.In reality, the Yankees need only to buy about another month of time before shortstop Didi Gregorius returns. When Gregorius had Tommy John surgery last fall, his target return date was some point during the summer. He is on pace to return closer to the early side of that projection.Whenever Gregorius is back, Gleyber Torres can return to second base. D. J. LeMahieu can float around the infield, as he was expected to do before the season, or handle third base, with Urshela serving as a backup.