After a ball was called to bring the count to 2-0 to Padres third baseman Chase Headley, Mesoraco turned to Fairchild, made a gesture with his arms out, took his mask off and began arguing. He was tossed as soon as he stood up.
"I think first and foremost, the game wasn't going as we hoped and I was a little frustrated with that," Mesoraco said. "Obviously, frustration got the best of me and I lost my cool there. I just disagreed with some calls. You want to stand up for your pitcher, because they can't do it out on the mound. That's what came out. I'm not perfect by any means."
The argument got more heated after Reds manager Dusty Baker came out to break things up. Mesoraco continued to fume at Fairchild and eventually fought around Baker's grasp and bumped into the umpire, seemingly knocking him backward.
"I couldn't tell if he touched him or not," Baker said. "[Mesoraco] was pointing his finger and then evidently he must have touched him. The second time, it looked like they kind of bumped each other and then [Fairchild] did a pretty good acting job like he was really bumped, you know what I mean?"
Baker grabbed Mesoraco and escorted him off the field.
The Padres were leading, 9-3, at the time of the ejection, and the Reds had already recorded five walks in the game.
It was the first ejection of Mesoraco's career. The rookie catcher may face a suspension for making contact with an umpire.
"I don't know how it works with the Commissioner's Office or anything like that," Mesoraco said. "Obviously if you end up hurting the ball club, that's something that you don't want to do. We'll see how it goes, but there's nothing I can do about it at this point."
Mark Clements is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.