The Mets' farm system delivered yet again in late June, when Steven Matz burst onto the scene, throwing seven-and-two-thirds innings, striking out six, and allowing only two runs while driving in four runs himself, to boot. Though he only made six regular season starts in total after suffering a strained lat muscle, Matz flashed similar potential every time he took the mound, finishing with a 2.27 ERA in 35.2 innings with above-average strikeout and walk rates. He went on to make three postseason starts, throwing 14.2 innings and allowing 6 runs, fine results for a rookie with fewer than ten major league starts under his belt.
Matz featured three pitches in 2015: a heavy, sinking fastball, a curveball that served as his out pitch, and a changeup that flashes plus and generates an above average rate of ground balls. Better yet, Matz has begun to tinker with the vaunted Warthen slider, and while it's unrealistic to expect a pitch as dominant as those thrown by Matt Harvey and Jacob deGrom, Matz has the arm slot and the talent to add another plus offering under Warthen's tutelage. Wrap that package up and you have a lefty with elite velocity, two above-average breaking balls, and an arsenal that generally keeps the ball on the ground. That's an arm worth getting hyped for, so long as Matz stays healthy.
Because of the arbitrary nature of prospect eligibility, Matz still qualifies as a prospect and is, unsurprisingly, the consensus top prospect in the Mets' system. Both Greg Karam and Jeffrey Paternostro wrote excellent spots on Matz for the Amazin' Avenue and Baseball Prospectus Mets lists, and they share similar optimistic views tempered somewhat by health concerns. Even with those durability questions, Matz is one of two easy favorites—along with the Dodgers' Corey Seager—for the 2016 National League Rookie of the Year award, which would give the Mets two winners in a three year span.
Matz would be a solid number two starter on plenty of major league teams, but with the Mets' embarrassment of riches, he's relegated to the fourth slot in the team's rotation. There are still things Matz needs to work on—his home run rate in 2015 was elevated, and the elite swing and miss curveball didn't really show up—but the prospect pedigree and baseline performance give plenty of reasons for optimism.
Consider also that had Matz had enough innings to qualify, his 21.2% hard hit rate allowed would have tied for the lowest in baseball with American League Cy Young winner Dallas Keuchel. That's a mark he won't sustain but a promising sign nonetheless. By midseason, Matz could be pitcher 1D in one of the best rotations in recent memory.