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Dylan Covey is baseball’s most improved pitcher

A change with his fastball has been very noticeable through six starts for this White Sox pitcher, and results are showing.

Chicago White Sox v Boston Red Sox Photo by Adam Glanzman/Getty Images

Earlier this week, our own Matt Provenzano put out a piece on the strides of Marco Gonzales this year, using the progress of him this season to show that prospect development is in fact not linear. We don’t have to reach far to find another example of this, though. Jumping over to the White Sox, Dylan Covey, a former first round selection of the Brewers and fourth round selection of the Athletics, has steered his career back in the right direction early here in 2018.

While not as a highly regarded a prospect as the aforementioned Gonzales, it’s not like Covey is a player that sprouted out of nowhere. He found himself on a handful of prospect rankings, notably coming in as the A’s #19 prospect in 2013 and #18 prospect in 2015.

Looking at season-to-season performance levels of Covey in the past will underwhelm you. Nabbed with the 131st overall selection by the A’s in the 2013 draft, he was coming off an unimpressive sophomore season at the University of San Diego, a season in which he struck out 50 and walked 43 in 81 innings of work. After a successful debut minor league season in 2013, Covey struggled mightily in 2014, posting a 5.46 ERA and 5.9 K/9 in 140 innings across two levels. He rebounded his prospect status with a good 2015 season in High-A, but then missed all but six starts in 2016 with a prolonged DL stint. With all these ups and downs, the A’s opted not to protect him from the Rule 5 Draft, where Covey would later be picked up by the White Sox.

With only 29.1 innings logged above the High-A level, the jump for Covey to the major league level was a struggle to say in simple terms. In 70 innings, he posted a 7.71 ERA and 7.20 FIP, while striking out a mere 13.3% of batters and walking 11.0%.

It wouldn’t be a stretch to say Covey was one of the worst pitchers in all of baseball last year. Among 204 pitchers with at least the 70 innings he had, he ranked 203rd in ERA, 203rd in FIP, 203rd in SIERA, and 204th in K-BB%.

Bottom 10 in SIERA in 2017

Name Team SIERA
Name Team SIERA
Chris Tillman Orioles 5.76
Dylan Covey White Sox 5.64
Hector Santiago Twins 5.57
Derek Holland White Sox 5.57
Andrew Cashner Rangers 5.52
Travis Wood - - - 5.51
Mike Pelfrey White Sox 5.5
Matt Cain Giants 5.45
Matt Harvey Mets 5.44
Bronson Arroyo Reds 5.42
Minimum 70 IP FanGraphs

There were problems all across the board, but the first one that pops outs is the home run rate, sitting at a prodigious 2.6 per nine. With a quick glance, you’ll notice that was aided by a robust 24.7% HR/FB. Diving a bit deeper, the overall issue came with flyballs. Minimum 50 fly balls allowed, he allowed the second-highest hard-hit rate on flyballs in a pool of 347 pitchers.

Highest Hard-Hit% on flyballs in 2017

Name Team TBF Hard%
Name Team TBF Hard%
Jordan Lyles 2 Tms 76 59.2%
Dylan Covey CHW 81 58.0%
Clayton Richard SDP 124 55.7%
Blake Parker LAA 52 53.9%
Matt Wisler ATL 55 52.7%
Tyler Duffey MIN 69 52.2%
Hyun-Jin Ryu LAD 118 51.7%
Tyler Chatwood COL 91 51.7%
Chad Bell DET 69 50.7%
Trevor Cahill 2 Tms 64 50.0%
Minimum 50 flyballs allowed FanGraphs

Covey needed to change something if he wanted to stick around with a big league club, and because he no longer needed to stick on a major league roster, he could work to get better in Triple-A. The early results down there were promising enough (2.33 ERA, 3.84 FIP, 22.2% K%) for him to get a second shot in the White Sox rotation fairly quickly. It was now at the major league level that he got to fully showcase the changes he made, and they sure have been drastic.

Overall, Covey has done a massive overhaul with fastball. Last year he threw a four-seamer 30.1% of the time. Through six starts this year, he’s almost totally abandoned it, throwing it at a 3.7% rate. He’s essentially replaced it with a sort of two-seam sinking fastball (Baseball Savant marks it as a two-seamer, Brooks Baseball has it as a sinker), which he threw 27.3% of the time in 2017, upping it to a 64.1% mark this season. His rate of increase with that pitch is at an unprecedented level among major league pitchers this year.

Minimum 30 innings pitched, he throws that pitch more than any other starter in baseball.

Top 10 sinker% among starting pitchers

Name Team IP SI
Name Team IP SI
Dylan Covey White Sox 35.1 65.3
Bartolo Colon Rangers 69.2 64.3
Jake Arrieta Phillies 69.2 61.6
Doug Fister Rangers 66 60.8
Steven Matz Mets 58.2 59.6
Andrew Heaney Angels 63.2 55.8
Clayton Richard Padres 88 55.3
Zach Davies Brewers 43 54.5
Kendall Graveman Athletics 34.1 53.5
Alex Cobb Orioles 56 53.5
Minimum 30 IP FanGraphs

The complete remodel with his fastball combined with a release point change has done wonders for Covey’s control problems too. The rate of pitches in the zone on his fastball has had a nice uptick, jumping from 50.0% to 57.1%, now comfortably above the league-average of 52.0%.

Brooks Baseball

And about that home run problem mentioned earlier? Well... increased sinking action on his fastball has benefited him greatly, as his hard-hit rate on flyballs is down from 58.0% to 32.0%, now below the league-average of 37.3%. Subsequent results fall right in hand too, as now zero of his 25 flyballs allowed have gone over the fence.

I try to not get worked over a small sample size, such as something like six starts, but when a player makes a dramatic change to his profile and results start to improve, it’s hard not to say something. Covey likely isn’t ever going to become anything flashy, but the White Sox might have molded a very capable major league starter with a few changes.