Let's Talk About Tyler Duffey's Curveball

Duffey, a former closer from Rice University and converted into a starter after the Twins drafted him, arrived at the organization with two viable above-average pitches in his fastball (four and two-seamers) and curveball, and he has also mixed in a work-in-progress change-up. Duffey told Twins Daily this spring that he considered his curve ball his best pitch and it shows. Any pitcher will tell you that the fastball is the foundation -- that sets up every pitch -- but the curve ball has been, as the French say, Le Unhittable.

With the exception of a few flares, a couple of seeing-eyes and one hanging fly which 40-year-old Torii Hunter in right failed to wrangle in, Duffey’s curve ball has been a zone-expanding, bat-missing machine. Just watch some of these swing that Duffey was able to induce in his start against Cleveland at Target Field last week.

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These are well-compensated, experienced, fully grown professional baseball players taking ridiculous swings usually reserved for hack golfers at a bachelor party after six beers while blindfolded.

To date, Duffey has done very little to disguise what is coming once he gets ahead: He has thrown curve balls 51% of the time in a pitcher’s count. Despite the ubiquity of scouting reports on pitchers, there is still some element of surprise that gives a rookie pitcher an advantage over hitters. You can hear about a pitcher’s repertoire and watch footage but until you experience it in the batter’s box and see it for yourself, the pitcher will have a slight edge. That may play a small factor in Duffey’s dominance over two consecutive lineups.

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However even when knowing the pitch is coming it still can cause hitters to look foolish. For example, during Thursday night’s contest Duffey unleashed a doozy of an 0-2 curve that had Orioles’ slugger Chris Davis completely flummoxed. Davis swung at the ball -- a pitch that would barely make it across the plate in the air. The Orioles successfully lobbied the umpire crew to say that Davis had made the world’s slightest contact with the ball and was therefore foul. With new life, Duffey delivered the exact same pitch in the exact same location which Davis could not manage to nick this time for strike three.

What makes Duffey’s curve ball so hellacious? It is the amount of spin he is able to generate.

According to his PitchFX spin rate, he is breaking off his curve at 1600 RPMs on average. Why is this important? Studies have shown that the higher the RPMs on breaking balls, the more the pitch moves and the higher the swinging strike rate typically is. Across the league, MLB pitchers have a 1500 RPM average (although ESPN/TruMedia’s database suggests it is closer to 1350). On the high end of that spectrum are guys like Oakland’s Sonny Grey (1898 RPM), Seattle’s Felix Hernandez (1858) and Houston’s Collin McHugh (1886).

It was in discussing McHugh’s acquisition that the Houston Astros shared a little secret in their methodology. According to the Bloomberg article in 2014 entitled “Extreme Moneyball”, the Astros analytics team identified McHugh, who was a castoff from both the Mets and Rockies organization, as a potential target because his curve registered such a high spin rate. McHugh’s curve was reaching nearly 2000 RPM. Duffey’s bender does not reach that strata but it is above average in spin rate nonetheless. Based on the 100 curves thrown, Duffey’s hook resides alongside Los Angeles’ Clayton Kershaw and Zack Greinke, Washington’s Gio Gonzalez and Arizona’s Jeremy Hellickson.

Through three starts, Duffey's curve sits among some of the game's best when it comes to spin. Who knows what lies ahead in the career for the big right-handed. Will hitters key in on his patterns? Will his fastball have enough oomph to support his curve? Will his change-up develop as a third option? If nothing else, Duffey's curve will prove to be a very valuable weapon out of the bullpen.