Chapman defended his actions after the win.
"I think the Angels were under the impression that we were stealing their signs," Chapman said. "I think this stemmed back to a couple games ago. They thought that we were relaying signs to our hitters from second base. He also thought that a couple guys on our team were peeking at the catcher's signs.
"[Graterol] kept staring at every single hitter as they were digging into the box, and that's not a very comfortable feeling. It's a little disrespectful to be honest.
"So, when I stepped into the box, I just let him know that we were not stealing their signs and that there was no need for him to be staring at us, and let's just get the game moving forward, and he obviously didn't take too kindly to those words."
Though Chapman said his language was clean, he believes Everitt took exception to him continuing the discussion, "and I guess if I thought it had been handled already I wouldn't have said anything," the rookie third baseman noted.
"Obviously I didn't intend for it to go down like this, but the way I looked at it was, I wanted to stand up for my teammates and stand up for myself. Even though we are a young group of guys, I feel like we deserve to be treated just like anyone else in the big leagues and respected by our opponents.
"So I did it out of respect for my teammates and respect for myself. I wanted to let him know that we didn't think that was OK, and it played out as it did."
Earlier in the game, Graterol stared down the A's Mark Canha, who said he was told in the second inning, "Stop looking at my signs."
Canha mentioned other young players, including Chad Pinder, were essentially being accused of much of the same, and he thought it may have been a "[manager Mike] Scioscia-Angels-Graterol tactic to make young players feel uncomfortable or something."
"They couldn't have seen me try to look at the signs, because I wasn't," he said. "I don't know if it was a tactic or if they actually thought I was."
Asked about the matter, Scoscia responded, "I just know that a couple of their guys, I don't know if it's their pre-pitch routine or what, they have a habit of glancing back. And on a day game or a night game when you can see shadows at a catcher's head, it's easy to look back and pick up some locations. So Juan was just saying, 'Hey, man, don't look back.'"
"They started picking signs, and that's it," Graterol said. "[Chapman] told me they don't, and we exchanged words, and that's it."
Chapman, who was replaced at the plate by Renato Nunez, earned brownie points in the A's clubhouse for his actions.
"I think he's a leader," outfielder Khris Davis said. "He's natural at it. He might be a rookie, but one day he's gonna be a vet and just lead the way."
"Obviously [Chapman] cares about the team, and he cares about me and Pinder and wanted to say something," Canha said. "I think it's important to have each other's backs. It was a nice thing to do. I told him we'd rather have the game than sticking up for me, but you can only take so much. It's a tough situation to handle."