Terry Collins would not acknowledge the roster move Thursday, but said the team would have an announcement about the rotation before Friday's game.
Jon Niese later told reporters that, as far as he's been told, he's pitching Sunday.
"Sunday's my day, that's the fifth day," he said, according to Mike Vorkunov of NJ.com (June 25, 5:41 pm).
According to ESPN NY's Adam Rubin, the team is likely to bring back the six-man rotation (June 25, 5:51 pm). John Harper of the Daily News says Sandy Alderson expressed concern about innings limits for the current staff (June 25, 5:58 pm).
According to Joel Sherman of the New York Post, a trade is not in the works (June 25, 2:53 pm).
Matz, 24, who grew up on Long Island, has gone 7-4 with a 2.19 ERA and 1.11 WHIP in 90 1/3 innings pitched (14 starts) for Las Vegas so far this season.
"I think the fastball was mid-90s, but it looks like he's handing you the ball almost," ex-Met Nick Evans, who has faced Matz in Triple-A, told ESPN NY's Adam Rubin (June 25, 4:10 pm). "It just explodes out of his hand. It's pretty impressive. ... He's definitely been the best arm we've seen in this league so far this year. The consensus on our team is he's the real deal."