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Danny Duffy's strategy on Sunday was almost perfect

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Five strikeouts in three innings.

Ed Zurga/Getty Images

Danny Duffy, pressed into starting duty because of injuries to Chris Young and Kris Medlen, made his first start of the season on Sunday. In three innings, Duffy threw 48 pitches, struck out five batters, walked two, gave up only hit, and allowed no runs. It was a heck of an outing -- the Braves truly had trouble making contact.

This will be a deeper dive into Duffy's start, so keep a few things in mind:

  • Duffy knew almost exactly how long he'd be in there -- 40 to 50 pitches. He could pace himself appropriately.
  • The Braves are not good
Those two factors likely affected his strategy, which was clearly to rely on the fastball. According to Brooks Baseball, Duffy threw his four-seam fastball 31 times and his sinker six times; the hard stuff amounted to 77 percent of his pitches. He threw only three changeups and eight sliders (Brooks Baseball classification, which will be used as much as possible).

Over the weekend, I wrote a prescription for what Duffy should do in the rotation to get better results. This is an evaluation of sorts against that prescription. The basics of it were that Duffy should locate his four-seam fastball higher, keep his changeup outside, and bury the breaking pitch (slider or curveball or whatever) low and outside to lefties/back foot to righties.

Overall, Duffy did a pretty good job of keeping his fastball up. His 2014-2015 data show a concentration of fastballs on the outside corner to lefties, inside to righties. The below zone profile shows the 31 four-seam fastballs from Sunday's game.

danny duffy sunday
It's a little scattered, but he definitely kept the ball more up compared to the chart in the linked article. That concentration of pitches on the left side of the chart above is just not there. The chart above does show both lefties and righties; splitting it out shows much more clearly that he stayed up and away from both hands.

Though Duffy did not actually keep his fastball up with two strikes, the overall results were nothing short of excellent. Duffy had eight whiffs on his four-seam fastball for a whiff rate of 25.8 percent. Of those eight whiffs, six were high fastballs. Duffy's average four-seam fastball velocity was 96.5 mph. Hitters just could not catch up.

Brooks Baseball did register six sinkers, only one of which was located high.

Duffy's eight sliders were buried mostly in that low-and-away corner to lefties. He got only one whiff, but the pitch was a strike six of the eight times. Duffy used it as an out pitch; it showed up only when he was ahead in the count (once when the count was even) and accounted for only 16.7 percent of pitches. Of the eight pitches, he got four swings. Those four swings resulted in three fouls and one whiff. Hitters were not quite ready for the slider whenever it came.

Duffy threw his changeup only three times, all to right-handed hitters (twice to Gordon Beckham and once to Daniel Castro). He got a swinging strike against Beckham on a 1-2 count; it was the first pitch not to be a fastball after six straight fastballs. He threw it for a ball against Beckham later and induced a weak groundout from Castro. The swinging strike and groundout were located on the outside corner; the ball was low and inside, a strange place to throw a changeup against right-handed hitters.

Overall, Duffy kept his fastball high, and it worked very well. Because he was throwing it hard and kept it up, hitters just could not catch up. Duffy did not have to go to his secondary stuff much, but it was effective when he did. Hitters likely sat fastball and were unprepared for anything else; they still could not hit it. Duffy tired a bit at the end, giving up both his walks in his final inning, but he was effective.

Should Duffy remain a starter, it is not likely that he will keep up 96 mph heat. Throwing three innings against a bad team is not the same as throwing seven innings against a good team. However, he made it through, averaging 16 pitches per inning. If Duffy has to let off the gas a little bit in order to stay in games longer, throwing fewer fastballs with less velocity, the strategy he employed in this game should still be effective.