After Boston rallied to take a 5-4 lead in the fourth, Guerrero singled off reliever Scott Atchison to reach base for the second time. With Matt Wieters at the plate and a 3-2 count, Vladimir Guerrero broke for second base. Wieters checked his swing and home-plate umpire Mark Wegner didn't indicate ball four or strike three.
Catcher Jarrod Saltalamacchia threw down to second base, where Marco Scutaro tagged Guerrero. Second-base umpire Mike Winters didn't make an initial call, because the Sox appealed Wieters' swing to Guccione, who ruled Baltimore's catcher swung. From there, Winters called Guerrero out.
Asked if the tag made contact with Guerrero, Scutaro said, "I tried. I don't know. I felt something, but I didn't watch the replay."
Guerrero was visibly upset about the call, motioning that he wasn't tagged. Showalter came out to argue the double play with Guccione, who immediately ejected Showalter.
"Take your pick, I think it was strikes," Showalter said, guessing why he was ejected. "I think it was arguing balls and strikes, I don't know. I was more frustrated about the 3-1 pitch on Wieters."
It was Showalter's third ejection of the season, two of which have come at Fenway Park.
Jason Mastrodonato is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.