Mets general manager Sandy Alderson would not disclose Harvey's infraction, but a source told ESPN on Sunday that the pitcher was suspended for not showing up to the ballpark on Saturday. Harvey's absence Saturday was first reported by Fox Sports, which also reported that a source close to Harvey said that the pitcher had a migraine and that there were possible communication issues with the team.
The New York Daily News reported that the ban stems from a compilation of issues dating back to last season.
The suspension apparently does not have anything to do with another recent Mets controversy. The team posted and then deleted a photo on social media Saturday that showed a sex toy in backup catcher Kevin Plawecki's locker, but an MLB source told ESPN's Jerry Crasnick on Sunday that the discipline for Harvey is not related to that.
Alderson said only that Harvey was sent home and that his suspension started Saturday. Left-hander Adam Wilk was called up from Triple-A to replace Harvey as the Mets' starter Sunday against the Marlins and was hit hard, giving up six runs and eight hits in 3 2/3 innings. New York managed only one hit in a 7-0 loss and was shut out for the first time this season.
"I don't know if I'd use the word frustrating," Jay Bruce said, according to the Daily News. "Obviously there are team policies, and when those aren't followed, action has to be taken. I don't know any of the details, I just know that Matt's not here today. He's going to miss a few days."
Manager Terry Collins addressed the team before Sunday's game.
"In order to be able to control things you've got to sometimes make tough decisions, and this is one of them," Collins said, according to the Daily News.
It was already shaping up to be a rough weekend for the Mets before Sunday's news. It was announced on Saturday that ace Noah Syndergaard will be sidelined through at least the All-Star break because of a torn muscle behind his right arm. He was officially put on the 60-day disabled list on Sunday to make room for Wilk.
The Mets also claimed lefty Tommy Milone off waivers from Milwaukee -- he was 1-0 with one save and a 6.43 ERA.
Collins indicated that he was aware that a suspension could be on the horizon for Harvey.
"There were some moves made last night because we felt this might occur,'' he said.
In addition, shortstop Asdrubal Cabrera left Saturday's game with a thumb injury suffered while diving for a ball. Alderson said that Sunday's MRI did not show ligament damage, and he hopes Cabrera is out a short time.
Also, left fielder Yoenis Cespedes, out since April 27 with a strained left hamstring, will return to New York on Monday for what Alderson said will be "an evaluation that is a little broader than just the hamstring, to try and get to the question of why he may have recurring hamstring injuries.''
Right-hander Seth Lugo and left-hander Steven Matz are both recovering from elbow injuries, while first baseman Lucas Duda has been on the disabled list since April 20 with a hyperextended left elbow.
Harvey is 2-2 with a 5.14 ERA in six starts this season as he comes back from surgery for thoracic outlet syndrome that ended his season early last year. He made only 17 starts last season, going 4-10 with a 4.86 ERA.
Harvey pitched well in 2013, when he went 9-5 with a 2.27 ERA, and in 2015, when he went 13-8 with a 2.71 ERA.
The Associated Press contributed to this report.