7:25pm: The Mets have announced that Matz has a partial tear of his lat muscle on his left side. He will be shut down for three weeks, then be reexamined. Marc Carig of Newsday has tweeted the text of the Mets’ announcement.
7:08pm: Matz’ injury is “not serious,” a source tells ESPN New York’s Adam Rubin (on Twitter). It does appear, however, that the Mets will skip Matz’s next turn in the rotation.
6:51pm: Mets starting pitcher Steven Matz has a lat injury and will miss several weeks or more, Andy Martino of New York Daily News tweets. The Mets were using a six-man rotation, an arrangement with which ace Matt Harvey had already expressed displeasure, so they will presumably just go back to five.
Matz entered the season as a highly regarded pitching prospect and only enhanced that status with 90 1/3 dominant innings for Triple-A Las Vegas — he posted a 2.19 ERA, 9.4 K/9 and 3.1 BB/9 in a notoriously difficult environment for pitchers. He made his big-league debut June 28 and allowed two runs in 7 2/3 while firing mid-90s fastballs and going 3-for-3 at the plate in a Mets win. He then pitched six shutout innings and struck out eight last Sunday.
Had Matz remained healthy, he might have met resistance at some point, and the Mets clearly have the depth to withstand a pitching injury. Losing a promising rookie for a significant period of time is, however, a blow to the Mets, who remain in the hunt for both the NL East and the Wild Card.