Tyler Skaggs, Sinkerballer?

When Tyler Skaggs looks back on his domination of the Houston Astros to open 2014 in twenty years, I’m willing to bet he won’t boast about it all that much.

But he should.

Pitching an eight-inning shutout Saturday night in his debut with the Los Angeles Angels, Skaggs held those Astros to four hits — all singles — while striking out five batters to just one walk.

Other than the fact that it was his first career road start in which he earned a winning decision, the most indelible aspect of Skaggs’ start was that his fastballs (i.e. four-seam and two-seam) were more smoldering than they’ve ever been — clocking in at an average velocity of 92.0 MPH — well above any of his other 13 career starts to this point to go with a career-high 94.5 MPH maximum velocity.

Not only that, but the 6-foot-4 southpaw induced a career-high 63.6% ground ball rate (minimum 15 PA) with both offerings, and against a Houston lineup that was exclusively made up of right-handed batters, to boot.

Skaggs FB April 5

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Skaggs pounded the strike zone with his fastball early, posting a 72.2% zone rate on 0-0 counts (well above his 51.5% career mark coming in) and often, accumulating a 66.1% overall zone rate (also above his 51.6% career zone rate) Saturday night at Minute Maid Park. Typically, when starters throw more fastballs in the strike zone, it equates to slightly fewer ground balls.

However, this was not the case for Skaggs this weekend, as his heaters generated an overall ground ball rate of 64.7%. Perhaps the more surprising and impressive part was that his four-seam and two-seams fastballs together garnered an increased 68.8% grounder rate (11 ground balls over 17 pitches hit in play) when located in the strike zone — an impressive feat considering the league-average ground ball rate on in-zone fastballs was 40.9% last season.

Of course, velocity isn’t the only thing that helps induce ground balls. Vertical and horizontal movement are also key.

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As we can see, Skaggs went to his sinker (aka ‘two seam’ fastball) much more frequently Saturday night compared to his career marks coming into, tossing it at a 38.95% rate juxtaposed to 15.43% from his debut in 2012 through last season.

The data provided by Brooks Baseball also says that his sinker was more than three MPH faster on average (92.72 MPH) Saturday in contrast to prior (89.93 MPH), and that the offering employed significantly more horizontal movement and less vertical movement. Consequently, we shouldn’t be surprised by his lofty ground-ball rate Saturday evening — the correlation between horizontal fastball movement and ground-ball rate for left-handers since 2013 is convincingly stronger than vertical movement.

Richard Justice of MLB.com wrote in March that Skaggs could be the key this season for a Los Angeles rotation that was fly-ball oriented (35.5% fly ball rate) in 2013. If he maintains the current velocity and movement on his ground-ball inducing two-seamer that dominated the Astros, then there’s no way he won’t be.

And that’s something worth boasting about.