Steven Matz: Matz was selected in the second round in 2009, from high school in East Setauket, New York. The Mets didn't have a first-rounder that year so he was the top pick. Unfortunately he didn't have an early opportunity to justify this, missing all of 2010 with Tommy John surgery and all of 2011 after the elbow did not bounce back quickly. He made just six starts in 2012 (this time due to shoulder problems) but they were good starts, with a 1.55 ERA and a 34/17 K/BB in 29 innings with just 16 hits allowed for Kingsport in the Appalachian League.
Matz finally put in a full season in 2013 and was quite good, with a 2.62 ERA, 121/38 K/BB in 106 innings for Low-A Savannah. 2014 has been just as strong so far: 2.00 ERA with a 17/3 K/BB in 18 innings for High-A St. Lucie.
Matz is a 6-2, 200 pound southpaw born May 29, 1991. Arm strength isn't the question here: he can hit the mid-90s and his fastball has good sinking action. As you might anticipate given his lost development time, his secondary pitches are inconsistent. His curve is erratic and he needs to use his changeup more often. Reports indicate that his A-ball success is due to aggressive use of a fastball that over-matches inexperienced hitters with velocity and movement.
Given the injury history and the issues with secondary pitches, the bullpen may be Matz's ultimate destination. However, it makes sense to use him as a starter for now. There is considerable upside here; if the curve and change continue to improve, and if his arm doesn't fall off, he could become a number three starter. Those are big ifs, of course. He should reach Double-A later this year and we'll get a better read on his future at that point.
Jacob deGrom: Drafted in the ninth round in 2010 out of Stetson University, deGrom was originally a shortstop but turned to pitching his junior year and was quickly successful. His pro career started slowly, Tommy John surgery costing him all of 2011, but he returned in '12 and was effective with a 9-3, 2.43 ERA, 96/20 K/BB in 111 innings in A-ball.
2013 was less impressive stat-wise with a 4.80 ERA and a 44/20 K/BB in 60 innings for Double-A Binghamton, followed by a 4.52 ERA with a 63/24 K/BB in 76 innings for Triple-A Las Vegas. He ate innings through and proved his durability. He's been excellent so far in '14: 1.57 ERA in 23 innings for Vegas, with a 21/6 K/BB, just 16 hits allowed and a 3.00 GO/AO.
DeGrom is a 6-4, 185 pound athlete born June 19, 1988. He throws easy strikes with a killer sinker that can hit the mid-90s and his changeup gets good reviews. The key issue for him is developing a better breaking ball, but whatever he's doing right now is working. It is likely we'll see him in the majors later this year and he's got a shot at being a number three or four starter eventually.