Arizona Diamondbacks pitcher Merrill Kelly accused Chicago Cubs third base coach Quintin Berry of stealing signs during Monday night's game, escalating tensions between the two teams and drawing a rebuke from Kelly.

Kelly expressed his displeasure following the Diamondbacks' 7-0 loss, stating that while player-to-player sign stealing is a long-standing part of baseball, a coach's involvement crosses a line. "Stealing signs is as old as baseball. I think it’s a little bulls–t when it comes from a coach," Kelly said. "If it’s a guy on second base and they see a grip in your glove or if the hitters can see something you’re doing with your glove, I think that’s fair game. I think guys have been doing that since the beginning of baseball. I think it’s a little bush league when it comes from outside that."

The incident, which saw benches yelling at one another mid-game, appeared to center on Berry relaying information about Kelly's pitches, particularly his changeup, to Cubs hitters. Kelly noted that the broadcast showed him glaring at Berry in the fifth inning while pitching to a left-handed batter. "That was probably the most egregious I’ve seen from coaches," Kelly added. "Everyone in this game is trying to get an edge wherever they can. Definitely not the first time a coach has relayed signs, but I think in that situation I think it should stay between the players."

While Kelly maintained a degree of composure, members of the Diamondbacks' staff reportedly engaged with the Cubs' dugout. Arizona's pitching coach Brian Kaplan was said to have yelled toward the home plate umpire and gestured toward Berry, while bench coach Brian Bannister appeared to confront the Cubs' bench. Cubs bench coach Ryan Flaherty reportedly responded with expletives.

Cubs manager Craig Counsell downplayed the confrontation, characterizing it as "gamesmanship that goes on every day in the league." Berry, on the other hand, appeared unfazed by the Diamondbacks' reaction, offering a smile and a verbal retort.

The game concluded with a Cubs victory, extending their lead in the National League Wild Card standings. The Diamondbacks, meanwhile, are now two games behind the San Diego Padres for the final wild card spot. Despite his frustration, Kelly acknowledged the need for self-correction, stating, "I got to take a look at what I’m doing because clearly he had something and obviously if he has it then other people will probably pick up on it as well. I gotta figure out and do better on my part to not give it away."