In his second start, Matz pitched six scoreless innings while striking out eight and allowing two hits in a win against the Los Angeles Dodgers. He had a 1.32 ERA, 14 strikeouts, and five walks over 13 innings across his first two games. Shortly afterward, Matz was placed on the disabled list for two months due to a partial tear in the latissimus muscle in his left side. Matz returned to the pitching rotation on September 6 with a no decision, but won his next two consecutive starts. Following a 5–1 win against the New York Yankees on September 18, Matz became the first player in Mets history to allow two runs or fewer in each of his first five career starts. He finished the regular season with a 4–0 record, 2.27 ERA, and 1.23 WHIP over six starts, with 34 strikeouts in innings pitched. Matz experienced back soreness caused by spasms behind his right shoulder blade near the end of the season, which forced him to miss his final regular season start and threatened to sideline him again; however, he played through it and remained on the Mets pitching rotation during the team's postseason run. He made three postseason starts: one each in the National League Division Series (NLDS), National League Championship Series (NLCS), and World Series.