The loss pushed the Rays to four games back in the American League Wild Card race.
Maddon appeared to be upset with home-plate umpire Hunter Wendelstedt's strike zone, which ultimately led to his getting tossed from the game, since arguing balls and strikes brings an automatic ejection.
The Rays manager argued with Wendelstedt for several minutes, much to the delight of the Fenway faithful. At one point, Maddon offered an expletive while motioning with his hands to illustrate what he felt to be the expanded width of Wendelstedt's strike zone.
"Obviously, I went out there to discuss the width of the strike zone," Maddon said. "And I never mentioned anything about balls and strikes. ... I said, 'Listen, I did not come out here to argue, I just want to know what's going on because my guys are talking about how wide it is.' And he didn't like me asking that question.
"Because I wanted to be respectful, because I walked out there and I thought I did it in a fashion where nobody else would know what was going on. I had no intention of getting kicked out right there. ... So I came back up after that and watched it and it was pretty egregious. There's no question."
Wendelstedt rang up B.J. Upton on a called third strike in the top of the fifth that appeared to be outside of the strike zone on replay. Upton barked at Wendelstedt after the call, but managed to avoid getting ejected. Then, John Jaso was called out on strikes to end the sixth, also on a pitch that appeared to be outside.
"I think anybody who watched that game and would be objective about things, I'll take whatever they have to say, because it's tough enough to beat [Josh] Beckett, but when he's getting pitches on the chalk lines, that makes it even more difficult," Maddon said.
The ejection was Maddon's sixth of the season and 22nd of his career.