With one out and nobody on in the bottom of the fourth inning, Jimenez threw a ball that hit Sandoval in the back. Sandoval had slid hard into second base earlier in the game, taking out second baseman Jonathan Schoop, although the slide appeared to be clean.
Home plate umpire Jordan Baker immediately signaled that Jimenez was ejected, causing the pitcher to exclaim and manager Buck Showalter to trot out of the dugout. Both benches were warned.
Orioles catcher Caleb Joseph also argued with Baker, and could be seen saying, "What are you talking about?" in response to Baker's explanation for the ejection.
Jimenez had not yielded a hit through 3 1/3 innings. The Orioles brought on relief pitcher Kevin Gausman, who had minimal warm-up time.
Gausman allowed two runs in 1 2/3 innings of work, as Red Sox catcher Ryan Hanigan's home run with a man on in the bottom of the fifth tied the game at 2-2.
Boston went on to win the game 3-2 on Xander Bogaerts's walk-off single.
Jimenez's ejection came five years to the day that he threw the lone no-hitter of his career while pitching for the Colorado Rockies.