The New York Mets scratched Matt Harvey from his scheduled start and suspended him for three days without pay for a "violation of club rules".
Harvey's ban was announced before the Mets suffered a 7-0 loss to the Miami Marlins in MLB.
Mets general manager Sandy Alderson did not disclose the specific violation behind the suspension, but reports claim 2013 All-Star Harvey did not show up to the ballpark for Saturday's game against the Marlins.
The Mets called up Adam Wilk from Triple-A Las Vegas to start against the Marlins.
"This was a team thing, and therefore it's going to remain with the team," manager Terry Collins said.
"I think they're all behind us. They're all behind the decision. In the long conversations I've had afterward, they said we've got to move forward and we've got to move forward fast."
"There are things that go on that you deal with every day that make the job difficult, but you know it comes with the territory," Collins added. "This is one of those... In order to control things, you've sometimes got to make tough decisions."
Harvey, who is coming off season-ending surgery for thoracic outlet syndrome in 2016, is off to a slow start. The 28-year-old right-hander has a 5.14 ERA in six starts.