Sandoval was placed on the injured list Aug. 14 because of right elbow inflammation. Henry Schulman of the San Francisco Chronicle reported Thursday there was a "fair" chance the veteran's 2019 season was over because of the bone chips in his elbow.
Sandoval was having his best season since he signed with the Boston Red Sox in November 2014, hitting .269/.314/.509 with 14 home runs and 41 RBI in 107 games for San Francisco.
The switch-hitting Kung Fu Panda had been especially productive against southpaws, as he hit .313/.353/.583 from the right side. He did, however, hit 11 of his 14 home runs as a left-hander.
Losing Sandoval for the remainder of the season takes away a productive bat from the Giants as they try to make a late playoff push. They are 5.5 games back in the National League Wild Card race.
Sandoval had proved versatile this season, making 45 appearances at third base, 23 appearances at first...and one on the mound.
The 33-year-old had saved his career in the Bay Area after a disappointing two-plus-year run in Boston. He recently discussed his comeback with ESPN's Marly Rivera:
"But I also put in a lot of work and made many sacrifices, and I wasn't ready to leave the game. I wanted to prove to everyone, especially my children and my family, and set the example for my children, that in spite of the things that may happen to you, you always have to fight on."
Sandoval will become a free agent following the conclusion of the season.