The procedure is likely Sept. 3 or 4 in Los Angeles and will be done by Dr. Neal ElAttrache, who evaluated the 2012 World Series MVP on Wednesday and determined he needed the procedure on his ulnar collateral ligament.
The 33-year-old Sandoval made a comeback with the Giants in 2017 after his release by the Red Sox, and he has been used in various roles by manager Bruce Bochy. Sandoval, on the injured list retroactive to Aug. 11 with inflammation in the elbow, was batting .269 with 14 homers and 41 RBIs in 107 games.
"This was a tough blow for us with the job he's been doing, both starting and coming off the bench,'' Bochy said.
Sandoval grew teary Saturday at the thought he might never make another play for the retiring Bochy, a "father figure" who resurrected the third baseman's career during a second stint in San Francisco.
But perhaps there's still a chance of another swing or two -- if both men have their way, and if Sandoval's ailing arm can handle it.
"He's like my dad, he always wants the best for me and he always cares about me. If he wants me to go out there and play I'll take one more at-bat for him," Sandoval said. "It's hard. He's one of the greatest managers I've ever played [for]. Not being around playing the last few weeks of his career, it's tough, but thank God he gave me the opportunity to play nine years for him and do everything I can for him on the field and off the field. Being part of those three World Series is the most important thing we did together."
The affection was mutual on Bochy's part.
"I'd love to have some fun with him here the last five or six weeks. He's just so much fun," Bochy said. "I've said this so many times, I just love his love for the game, his enthusiasm. Every day, he's got a smile on his face. We haven't seen that because he's been a little down because of the injury. Anyway, for Pablo long term, this is the best thing. I'm glad they have it figured out and will get it fixed."
Although Tommy John surgery is more commonly associated with pitchers, a number of position players have also undergone the procedure in recent years, including Salvador Perez, Didi Gregorius, Corey Seager, Travis d'Arnaud and Gleyber Torres.
While Sandoval is set to become a free agent, San Francisco athletic trainer Dave Groeschner said the club's longtime strong relationship with Sandoval makes it a case in which the Giants will monitor Sandoval's progress and get him set up with physical therapists in the Miami area, where he spends the offseason.
Groeschner is optimistic Sandoval will rebound once more and get back on the baseball diamond -- just as he did coming back this year from a torn right hamstring.
"He works hard. He's been through this with different body parts. He knows the process,'' Groeschner said. "Last year he had his hamstring done. That was a pretty major surgery. He came back in spring training and looked great, and nobody really asked about it. He worked his tail off at the end of last season and all the way along. I don't anticipate anything different from Pablo.''
Last August, Sandoval's season also ended prematurely with the hamstring injury. He learned from that experience.
"I've been in this situation before and I know how to handle it. I know how to work hard and come back stronger for next time, or next year," he said. "It's tough, but it's not the end of my career."