DeGrom was initially promoted last week to pitch in the bullpen for the Mets, but he immediately stepped in to the rotation when Dillon Gee was put on the disabled list. He responded by throwing seven innings, while surrendering one run to the Yankees.
Including his work at Triple-A Las Vegas, deGrom's debut Thursday was just the second time in eight starts this season that he pitched a full seven innings. It was the third start he went six or more innings and allowed one run or fewer. And, according to Bill James's game score, it was the second-best outing of his 2014. However, this time, instead of doing it against Pacific Coast League, he did it against the New York Yankees... in his big league debut.
He threw his four-seam fastball, which averaged 94 mph, on 47 pitches, or 52 percent of the time. He added another nine sinkers, which also averaged 94 mph. His changeup was his most-used off-speed pitch with 17 tosses, averaging 85 mph. He threw nearly as many curves (8) at 80 mph, as sliders (10) at 85 mph. All four pitches were thrown with above average velocity (Brooks Baseball, May 16). While the movement on his fastball was average- to a-tick-below, he showed both above -average movement laterally and vertically on his curveball.
However, he struggled with his slider. He hung a slider in the middle of the plate, if down, to Alfonso Soriano, who ripped it into left-center field for a double, driving in the game's only run. He missed the strike zone with six of the 10 sliders he attempted.
The changeup was his most effective off-speed pitch, boasting both the highest strike percentage and best whiff rate of any of his secondary offerings. Almost as important as what he threw, was where he threw it. He kept the ball down, especially to left-handed hitters.
DeGrom's story is pretty simple: while rehabbing from Tommy John surgery in 2011, he learned a two-seam fastball from Johan Santana. A strong natural athlete, deGrom paired an easy delivery with lots of sinkers and four-seamers at the bottom of the strike zone to cruise through the minors and to the big leagues.
DeGrom, who will turn 26 in June, has significantly improved all three of his secondary pitches since becoming a pitcher full-time after the draft four years ago. As recently as 2012, when he only had a slider and a changeup, though he could throw the pitches for strikes, they were both comfortably below-average. Now, they are quite usable. The Mets taught deGrom the curveball in 2013 when his slider was making only halting steps forward. By this spring, scouts who saw deGrom in Spring Training saw the slider and curve ball as big league pitches.
He has taken a step forward in Triple-A this year, lowering his ERA from 4.64 in 24 starts in 2013 to 2.58 in seven starts in 2014. He's done it, not through major changes in his walk or strikeout rates, but through limiting hard contact. He's bumped his groundball rate from 44 percent in 2013 to 55 percent in 2014. That's mostly come at the expense of his line drive rate, which is down from 20 percent in 2013 to 10 percent this year.
Can he succeed with this kind of profile at the big league level? Roughly league average strikeouts and walks and lots of ground balls? Certainly. Mets Pitching Coordinator Ron Romanick compared deGrom to tw0-time all-star Bobby Witt. Witt ran a career 105 OPS+ and was no star, but was a reliable member of a big league rotation.
If deGrom struggles with throwing his slider or changeup, and turning over a lineup over a third time, as a starter there will be a role waiting for him in the bullpen where he can really turn his velocity loose and rely even more heavily on letting his sinker dive in the mid-upper 90s.