The Chicago Cubs made a surprising move with their superstar slugger after he reached a career low, and it has garnered a strong reaction from the leader of their hated rival.

After acquiring outfielder Kyle Tucker from the Houston Astros via trade for his contract season, the Cubs opted to give the slugger a mental reset after a hot start devolved into a career-worst slump at the plate. After earning his fourth consecutive All-Star bid earlier this year, Tucker was slashing just .184/.333/.211 with no home runs across 28 days before being benched.

“The situation has turned ugly, with Tucker getting booed at Wrigley Field for not producing and not running to first base,” Patrick Mooney wrote for The Athletic. “His numbers since the beginning of July are disappointing and conspicuous, especially given the current gap in the National League Central between the Cubs and (Milwaukee) Brewers.”

As the Cubs continue a series against the division rival Brewers without Tucker, Milwaukee’s skipper Pat Murphy spoke out about the reset, claiming there is more going on than the Cubs are letting on.

“I think Tucker is hurt,” Murphy said during an appearance on WSCR-AM 670 The Score Chicago. “I don’t have any information, but Tucker’s not the same. He’s hurt, and he’s playing through it. He’s such a class kid that he probably doesn’t mention it to anyone.”

Cubs fans might have mixed feelings to hear that their star player could be dealing with an injury, rather than merely a mental slump. On the one hand, a physical issue might be more directly addressed. On the other, it could mean Tucker takes longer to recover and return to the lineup.

Either way, it seems like the Cubs will need their star outfielder back sooner rather than later if they are going to have a chance of challenging the Brewers for the division. Whether it’s a mental or physical problem, the team is hoping Tucker can recover quickly and get back to his All-Star form at the plate.