Jacob deGrom of the New York Mets was one of the best rookies in baseball in 2014. He posted a 2.69 ERA, 2.67 FIP with a 144/43 K/BB in 140 innings. He racked up 3.0 fWAR, which made him the fifth-most valuable rookie pitcher in baseball behind Collin McHugh of the Astros (we'll look at him tomorrow), Marcus Stroman of the Blue Jays, Dellin Betances of the Yankees, and Masahiro Tanaka of the Yankees.

Jacob deGrom? Mets fans were familiar with him pre-season, but he was not a hot prospect on any national lists. Here's his background.

DeGrom was a ninth round pick in 2010 from Stetson University in Florida. He began his college career as an infielder and didn't pitch full time until the spring of his draft season, but his athleticism and arm strength stood out. He posted a 5.19 ERA with a 22/6 K/BB in 26 innings for Kingsport in the Appalachian League after signing, but gave up 35 hits. I didn't rank him in my 2011 book.

I didn't rank him in my 2012 book either, since he blew out his elbow and missed all of '11 with Tommy John surgery. However, he got back on the mound in 2012 and was very effective, posting a 2.51 ERA and a 78/14 K/BB in 90 innings in Low-A. Sally League sources were enthusiastic, prompting this report entering 2013:

SLEEPER ALERT!! DeGrom was drafted in the ninth round in 2010, out of Stetson University in Florida. He was mainly a shortstop in college and has the lanky athleticism that goes with that background. He missed 2011 recovering from Tommy John surgery, but came back healthy and effective in 2012, pitching very well at both levels of A-ball. DeGrom threw 89-94 in college but was up to 93-95 last year, at times reportedly hitting 97. His slider and changeup were also said to be better than he showed in college, and his control is sharp. He needs innings and experience, and it is unclear if he starts or relieves in the long run, but given his background I think deGrom made a lot of progress last year and bears close watching in 2013. Grade C+.

DeGrom's 2013 season brought mixed results: 4.80 ERA with 44/20 K/BB in 60 innings with 69 hits for Double-A Binghamton, along with a 4.52 ERA with a 63/24 K/BB in 76 innings for Triple-A Las Vegas, with 87 hits. He was hittable but note how his strikeout rate actually increased at the higher level, perhaps a sign that he was getting ready to break through for '14. Here's the report from the 2014 book:

A ninth round pick in 2010 from Stetson University, DeGrom reached Triple-A last year and should appear in the majors sometime in ’14. The former shortstop has a 92-97 MPH fastball which he locates well. He’s developed a fine changeup, but his breaking ball remains so-so and is reflected in a non-outstanding strikeout rate. It could use more work and additional Triple-A innings would be useful. DeGrom looks like a future number three or four starter to me, with bullpen work a backup option to keep in mind if his breaking ball doesn’t sharpen up. Grade C+ (note below)

The Grade C+ in the book was too low; I increased that to a B- in mid-January after more detailed review of the stats, scouting reports and video but forgot to change the book comment to match up with the final Mets Top 20 list.

As you know, deGrom opened up with seven starts this spring with Las Vegas, getting those "additional Triple-A innings." He was excellent, was promoted to the majors, and remained excellent.

So what happened? Simple: the breaking stuff came around.

The fastball and change-up were already there in the low minors, but he's polished up his curveball and slider to go with it. Eno Sarris at Fangraphs broke this down in August, noting the addition of power to the slider and a more defined curve. As Sarris wrote, deGrom now has five effective pitches, the arsenal ". . .development has given him five pitches with different movement and different velocities: two 93 mph fastballs, an 87 mph slider, an 84 mph change and a 79 mph curve."

What happens now? DeGrom looks real to me; there's no question about his stuff and the statistics are sharp. Heck, he was getting better as the season progressed: he posted a 34/4 K/BB over 21 innings (four runs) in his last three starts; the league was not catching up with him, not yet anyway.

DeGrom is a sleeper who woke up, a textbook example of an organization taking a rather raw but athletic player and turning him into a pitcher. That takes good scouting and good coaching, but it is the player who ultimately makes it happen.