Tyler Duffey will be finishing off his fifth season since making his major league debut in 2015. It has definitely been a bumpy ride after a successful taste of the majors in 2015. He came back as a starter in 2016, did poorly, and was eventually moved to the bullpen for 2017 and 2018 before something finally clicked this season.
This front office clearly saw something in Duffey to hold onto him during the times he was struggling. The Twins brass will not hesitate to let a young pitcher go if they do not see a future with them, and Duffey has proven them right in a huge way this season.
There was definitely something off or something to be changed with what Duffey was doing before this season, and the first place to look is his pitch usage. Things were simplified to throwing his curveball 52% and his fastball 46% of the time. This FanGraphs pitch types graph shows the change well.
Both pitches have been outstanding, and the fastball has been key to unlocking the breaking ball even more. Duffey has touched 97 MPH this season while averaging out at 94 on the fastball, a new career high. (Thanks Wes Johnson). He is allowing just a .202 AVG and .639 OPS on the season which is equivalent to what Joey Rickard is hitting for the Orioles.
The curveball is the pitch he has always been known for, and he has shown it off this season for sure. Throwing it over half the time, he has allowed a .208 AVG and .608 OPS against it while generating a 14.2 swinging strike% on the pitch. A comparison for that stat line would be what Jace Peterson has done for the Orioles this season. The Orioles are awful.
Now let’s talk some more about the results. He currently holds a career best 2.86 ERA that ranks 26th among AL relievers. He is also striking out more players than ever before at a 30% rate and that ranks 18th in the AL. He has turned himself into a top thirty relief pitcher in the American League and most fans have no idea.
He has been excellent all season, and he may actually be at his best right now. Through twelve games in August, Duffey has not allowed a run while boasting a K/9 of 12.0 and allowing an OPS of just .494 so he is stepping up even more as the division race heats up.
To my surprise, Duffey has quietly been better than both of the relief pitchers the Twins acquired at the deadline. He leads Sergio Romo in H/9, K/9, swinging strike%, ERA, AVG against, and OPS against. Romo and Dyson are both very good relief pitchers, but Duffey may be the best of that bunch. However, Duffey has not been used in spots with as much leverage as Dyson and Romo, which seems strange especially considering those two weren’t on the Twins all season. The Twins were giving high leverage spots to Ryne Harper or Blake Parker instead.
Duffey is overdue for some positive appreciation because he has been excellent this season despite constant hate against the bullpen. He is the poster boy for how teams may start building their bullpen: start with two or three solid guys you can trust and then throughout the season plug in a lot of different young guys and see what works. It’s looking like the Twins may have found a bullpen weapon for the next few seasons.