But whatever it was, both managers and two pitchers were ejected in Sunday's 9-4 win for the Nationals at Chase Field, after a series-long swap of hit-by-pitches from the two teams.
Home-plate umpire Rob Drake issued a warning to both benches in the fifth inning after D-backs starter Ian Kennedy plunked Nationals right fielder Jayson Werth on the left shoulder for his third hit-by-pitch of the series.
Two batters later, Kennedy nicked the jersey of Michael Morse but was allowed to stay in the game.
"Once we give warnings, if we deem it's intentional, then there are ejections," crew chief Gary Darling said. "The rest of it will be in our report to the league."
Kennedy said there was no intent in his hit batters, that he threw two-seam fastballs that just got away and that he agreed with Drake's decision not to throw him out.
"I think he was paying attention," Kennedy said. "He was a very good umpire, we were pounding [Morse] in during this series, and it was great on his part to see that, because, obviously, it just nicked his jersey."
But an inning later, Marquis hit Upton -- the right fielder's fourth hit-by-pitch of the series -- and was ejected, along with Riggleman, per MLB rules.
"We aren't throwing at anybody," Riggleman said. "We are trying to win the game. We don't want [Marquis] coming out of that game. He doesn't want to come out of that game. It's freakish that the same guy kept getting hit, and I'm disappointed that Jason didn't get to pitch, but somehow or another, we came out with a win."
Two innings later, D-backs reliever Esmerling Vazquez hit Danny Espinosa and both he and Gibson were shown the door.
"Batters get hit in games," Gibson said. "It was a good baseball game, that's the way I look at it. There was no intent there -- we were playing baseball. I had no problem. The umpires did what they thought was right and we play by the rules."
In the 11th, Espinosa was once again hit by a pitch, but D-backs left-handed reliever Joe Paterson wasn't ejected.
When asked after the game if the crew deemed only the sixth and eighth-inning hit-by-pitches from Marquis and Vazquez intentional, Darling said, "That's right."
Anthony Fenech is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.