With one out and Boston trailing, 5-4, Napoli laid off what he thought was an outside pitch from Ross Ohlendorf, but home-plate umpire Todd Tichenor called strike three. Napoli walked off the field upset and was later ejected from the dugout. Farrell came out in protest and also got the boot.
Farrell had also argued when Dustin Pedroia struck out looking to end the seventh.
"I thought there was a number of fastballs we felt that were off the plate away," Farrell said. "Despite the fact that their pitcher hits the glove, he was set up on the white chalk line on the left-handed batter's box. We felt like he was given a number of pitches that were not strikes that were called strikes."
Napoli's strikeout came just one batter after Hanley Ramirez hit a two-run home run to cut the Rangers' lead to 5-4. After Napoli's out, Brock Holt struck out swinging to end the inning.
Napoli, who wasn't available for comment, also struck out looking in the second inning and finished 0-for-2 with two walks.
Cody Stavenhagen is an associate reporter for MLB.com.