With one out in the third inning and the Mariners trailing, 2-1, Bradley, who started the game in left field, dropped his bat and began taking off his batting gloves after the called third strike and was immediately tossed by Bellino.
That prompted a visit from Mariners manager Don Wakamatsu, who, in discussing the matter with the umpire, claimed Bradley's actions were a product of mistakenly thinking it was the last out of the inning.
"In all fairness to Milton, I thought he thought there were three outs," Wakamatsu said.
"[Bellino] said he couldn't do that," Wakamatsu said. "I said, 'Do what?' I said, 'Go back [on the replay] and look at his actions and tell me he didn't think there were three outs.' I thought it was an overreaction."
Ryan Langerhans came into the game to replace Bradley, whose ejection came in the game on the Seattle schedule immediately following the Monday ejection of starter Cliff Lee for throwing a pitch that sailed near the head of D-backs catcher Chris Snyder.
Lee on Wednesday received word that he was suspended for the first five games of the regular season. Lee is expected to appeal the decision.
Doug Miller is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.