Steven Matz’s refined sinker has been crucial to his mid-season resurgence

Photo credit:John E. Sokolowski-USA TODAY Sports
Thomas Hall
2 years ago
Several months ago, there were plenty of question marks surrounding the Toronto Blue Jays starting rotation and its lack of depth, making it one of the most obvious weaknesses of the team. Fast-forward to the final stretch of the 2021 season, those same concerns no longer remain.
Considering starters like Tanner Roark, Tommy Milone, Anthony Kay, and T.J. Zeuch were consistently making starts for this club earlier in the season, there’s no question the starting rotation has come a very long way since then. While the pitching staff is currently headlined by Cy Young candidate Robbie Ray, trade deadline acquisition Jose Berrios, and breakout rookie Alek Manoah, Steven Matz has also served an important role over these last two months.
Granted, the start of Matz’s tenure with the Blue Jays didn’t take off smoothly as he proved to be fairly inconsistent throughout the first half of the schedule. Despite allowing one run or fewer over his first three starts of the campaign, he surrendered three runs or more in each of his next four starts, ultimately leading to some extremely mediocre results.
In total, the 30-year-old made 18 starts and compiled 90 1/3 innings pitched from April-July, recording a 4.58 ERA, 4.01 FIP, 102 ERA-, 95 FIP-, .275 OPP AVG, .335 OPP BABIP, 23.6% LD rate, 44.6% GB rate, 31.7% FB rate and a 15.1% HR/FB ratio.
Unable to count on Matz, there was some discussion inside the Blue Jays organization about transferring him to the bullpen following the acquisition of Berrios at the trade deadline. Just as the coaching staff was about to make its decision, teammate Ross Stripling suffered an oblique injury, opening the door for the former New York Met to remain in the starting rotation down the stretch.
Running with this opportunity, the 6’2″ hurler has since flourished under the guidance of pitching coach Pete Walker and the rest of the staff, which has helped him enjoy dramatically more consistent results since the start of August.
Turning a corner on his first-half struggles, the left-hander has totalled 50 1/3 innings over his nine starts, producing a 2.50 ERA, 3.48 FIP, 56 ERA-, 82 FIP-, .231 OPP AVG, .275 OPP BABIP, 16.4% LD rate, 48.0% GB rate, 35.5% FB rate and a 7.4% HR/FB ratio.
Despite featuring four pitches in his arsenal, Matz’s mid-90s sinker – his primary weapon – has sparked this incredible run since the trade deadline passed, thanks in part to some mid-season adjustments.
Starting with its pitch usage, the former second-round pick utilized his sinking fastball less than 50 percent of the time from April-May, however, he’s increased that percentage as the season has gone on as its usage ranged between 53%-59% during the summer months. Reaching a season-high in September, he’s thrown his primary heater 60.5%, which is its highest usage since 2019.
Digging deeper, Matz has also been advised to make a slight mechanical adjustment involving the release point of his sinker – something that may have been plaguing him earlier in the season. Undergoing this modification at the start of August, the hard-throwing lefty has altered his arm angle, gradually shifting it away from his body at the point of release.
Putting this transformation into perspective, Matz’s horizontal release point on his sinker averaged between 1.73-1.79 feet through the first four months of the 2021 campaign. But since then, it’s increased significantly and has risen to 2.26 feet in September, which is the largest horizontal release point among all of his pitches this season.
Now, this may not seem like a massive difference, but for any pitcher, the smallest changes can still have a huge impact on their performance. For the New York native, this mechanical adjustment has allowed him to improve the command of his sinking fastball, particularly against right-handed hitters.
From April-July, Matz’s sinker was primarily located within the inside half of the strike zone, although it did leak into the lower quadrants at times and wasn’t positioned along the edges of the 17-inch square nearly enough as well.
But thanks to this mid-season adjustment, Matz has been able to overcome those exact issues over these past couple of months, allowing him to dominate the top right quadrant of the zone with his primary heater.
As a result of his improved command, the 2016 National League Rookie of the Year candidate has been dramatically more effective with his sinker, as it hasn’t allowed anywhere near as much contact or power. In turn, it’s transformed into one of his most reliable weapons, which wasn’t the case prior to these changes.
Proving to be extremely reliable, Matz’s sinking fastball has allowed just a pair of home runs, a .244 AVG, a .247 xAVG, a .354 SLG, a .404 xSLG, a .110 ISO, a .273 BABIP, a .303 wOBA, a .324 xwOBA and a 90.0 mph average exit velocity over 68 batted-ball events against right-handed hitters since Aug. 1, according to BaseballSavant.com.
In comparison, it surrendered four home runs, a .323 AVG, a .301 xAVG, a .496 SLG, a .493 xSLG, a .173 ISO, a .435 BABIP, a .384 wOBA, a .379 xwOBA and a 91.8 mph average exit velocity through 89 batted-ball events against righties from April-July.
With fellow starter Hyun Jin Ryu sidelined with neck tightness, paired with his alarming 8.10 ERA and 5.12 FIP since Aug. 8, there seems to be an opportunity in front of Matz that could potentially earn him a start or two in the postseason, that is, if the Blue Jays qualify. While it’ll be imperative to maintain these impressive metrics through the rest of the regular season, there’s no hiding the fact that he’s become the more reliable hurler between the two.
Considering Ryu entered this season as the team’s ace, it’s been beyond puzzling to watch him perform inconsistently over an extended stretch, especially given the way he dominated the competition in each of the last three seasons heading into 2021.
But for Matz, who’s slated to become a free agent this winter, a strong finish to his inaugural campaign with Toronto will almost certainly increase his value on the open market in the coming months, which could possibly include a return to Canada’s team.

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