Tony Zych may be just 27 years old, with just 72.2 innings of work in three MLB seasons; however, he’s had to evolve more in those three short years than most pitchers do in a career.
The Mariners acquired Zych from the Cubs in 2015 as a high-octane reliever with a sharp slider to boot. He finished the year with the big-league club in the ‘pen with a promising 2.04 FIP and 11.78 K/9 in 18.1 innings. He set off to improve on a solid debut stint, boasting a 14.25 K/9 in his first 12 innings before heading to the disabled list with a shoulder injury. He went on to only appear in two more games that season.
Bicep surgery in October 2016 yielded a late start to the 2017 season. On the bright side, it also gave way to his first season with more than 20 innings. In fact, he more than doubled that number, logging 40.2 innings for the Mariners. Unfortunately, the injury bug bit Zych again, this time with an injury that is far too familiar to Mariners fans: the dreaded flexor bundle strain. That’s the same injury that magically morphed into a UCL injury for Drew Smyly and limited Shae Simmons to 7.2 IP last year. Zych nearly returned to action down the stretch last season, but was ultimately shut down prior to the end of the year.
The injuries that have plagued Tony’s young career have seemingly left their mark. His K/9 in 2017 reached a career low of 7.75. His velocity has declined each of his three years in the majors, which doesn’t feel like a coincidence.
Only time will tell how he will bounce back from the flexor bundle strain, but it’s hard to bank on his velocity storming back into the upper-90s.
But while Zych’s velocity steadily decreases, he’s countered with a retooled slider. His slider’s spin rate has increased significantly over each of the past two seasons, which has allowed Zych to remain effective with less gas on his heater.
While his slider isn’t generating the whiff rates it was in 2015 and 2016, the increased horizontal movement on his breaking ball has yielded less threatening contact. Hitters managed a measly .167 BABIP and .050 ISO against Zych’s slider last year; both mark the lowest scores of his career for that pitch.
As far as Zych’s fastball goes, the decline in velocity has caused his whiff rate to drop nearly 9 percent from 2016 to 2017; however, his fastball is inducing more grounders than ever before. Nothing really jumps out as an indicator of why Zych’s fastball is forcing more ground balls; however, it could be related to a change in spin rate for his heater. Unlike his slider, his fastball has seen a slight decrease in spin rate.
This study from Fangraphs suggests that lower spin rates on fastballs yield higher ground ball frequencies. Even a decrease as gradual as Tony’s fastball spin rate has proven to be enough to keep even more balls on the ground, producing less dangerous batted ball outcomes.
Who knows? Maybe an offseason to recover from a season that started and ended with injuries will prove to be what Zych needs to regain his early-career velocity. If not, the adjustments he’s made position him for another productive year out of the ‘pen, health permitting.