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Peripheral numbers back up the improved results over Danny Duffy’s last four starts

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Yes, Danny Duffy’s ERA in his last four outings is down 4.78 points compared to his first ten outings, but there’s more to it than that.

MLB: Minnesota Twins at Kansas City Royals Jay Biggerstaff-USA TODAY Sports

Before his start in Texas on May 24, Danny Duffy’s ERA had swelled to a season high 6.88 in 10 starts. He wasn’t striking many hitters out, he was walking far too many, he was giving up nearly 2.5 HR/9 innings, and Duffy made zero excuses for his efforts. He wore the blame on his shoulders and promised to be better.

Well, he has been. Over his last four starts Danny Duffy’s ERA is a measly 2.10 and the Royals ace looks like just that again. The return of good Danny Duffy is a welcoming sight to sore eyes in Kansas City, though it’s fair to wonder if this is the Duffy we should be expecting long-term, or if the 6.88 ERA Danny Duffy will rear its ugly head again.

Fortunately for us, I think Duffy is on the right track to sustained success. On the surface, things can look a bit murky. Duffy’s ERA is down 4.78 points over his last four starts, but he’s also not striking as many hitters out. Though, he’s walking fewer batters and also giving up less home runs. So, which one is it? Is he actually getting better, or has he just been lucky? While it’s fair to contemplate, here are some positive signs that Duffy is making a turn in the right direction.

  • In 10 starts before May 24, Danny Duffy was inducing weak contact on merely 9.6% of the pitches that he threw. In four starts since, that number has gone up to 12.2% which is top 15 in baseball for pitchers with at least 300 pitches thrown in that time. Inducing more weak contact? Check.
  • In 10 starts before May 24, Duffy was inducing swings and misses on 10.2% of his pitches thrown. In four starts since, that number has gone up to 11.2%, which puts him in the top 12 in all of baseball in that category (min. 300 pitches in that time). Induce more swings and misses? Check.
  • In 10 starts before May 24, Duffy was giving up home runs at a rate of 2.47/9 innings. In four starts since, that number has plummeted to just 0.7 home runs/9 innings. Give up fewer home runs? Check.

When digging deeper than just your typical ERA, strikeouts, and walks, we can see that all of the numbers surrounding these statistics are improving as well. Not only is Danny Duffy having better boxscore results, but the stuff that you don’t find on your typical boxscore is improving as well. But why the sudden, drastic improvement?

On Sunday, arguably Duffy’s best start of the year to date (7 IP, 0 ER, 10 K, 3 BB), Duffy threw more changeups (34) than he has in any start so far this season. He didn’t give up a single hit on his changeup all afternoon and the pitch looked particularly filthy on Sunday. Changeups help pitchers to keep hitters off their fastball, and make for a terrific third offering when they’re being used correctly. Duffy used his changeup to perfection on Sunday and I wouldn’t be surprised to see him using it more often down the road.

Duffy’s next start would theoretically be on Sunday, since the Royals had two off days this week, but nothing has been announced just yet. I’ll be watching closely to see how Duffy looks against the Houston Astros and one of the best lineups in all of baseball.