The play may have at least played a part in his early exit.
"[The dehydration occurred] during the game," manager John Farrell said. "Whether or not going first to home was a contributing factor to that, he was past the 45-foot mark when the ball was picked up in right-center field and you think you're in pretty good shape to score there. The weather, possibly the first to home, I first became aware of it when he came out."
Infielder Josh Rutledge, playing in his first game since being acquired from the Angels on Monday, replaced Sandoval at third base to begin the sixth.
Sandoval's debut season in Boston has seen a dip in production from the 28-year-old who played a pivotal role in the Giants' run of three World Series victories in five seasons. He is batting .262 with a .381 slugging percentage and has committed 12 errors in the field this season.
Farrell acknowledged the conditioning issues that Sandoval has battled in the past.
"You know, that's something that Pablo's dealt with his entire career," Farrell said. "It continues to be addressed. I can't say tonight is a direct result of that, but there are ongoing efforts to support that, to try to get him in the best shape possible."
However, the skipper also admitted that Sandoval should have better responded to the aggressive send by third-base coach Brian Butterfield.
"Again, where the ball was picked up, recognizing there was nobody out in the inning, where the ball was picked up in relation to where he was in the basepaths," Farrell said, "you think that's a run that should score. Whether or not he was declining in speed because of the onset of the dehydration, I can't answer that in that split-second moment."
Alec Shirkey is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.