Article: It’s Time to Start Trusting Tyler Duffey in High Leverage Situations

[Andrew Thares]

All winter, the biggest area the Twins needed to address was the back end of the bullpen. However, the only reliever that they signed to support the bullpen was Blake Parker, which was a little underwhelming to many Twins fans. Fortunately, there have been a few guys, like Taylor Rogers and Ryne Harper, within the organization that have stepped up in a big way so far this year. Well, as it turns out, there is another reliever within the organization who has pitched very well this year, and it is time to start throwing him in bigger spots. I am talking, of course, about Tyler Duffey.When Tyler Duffey was coming up through the minor leagues, he was very much the Terry Ryan era sinker-slider type pitcher who relied heavily on getting groundballs instead of strikeouts. When Duffey was first called up in 2015, he was an effective starting pitcher with a 3.10 ERA in 10 starts. However, 2016 didn’t go so well for Duffey, and he was transitioned to the bullpen for the 2017 season. Over his first two seasons as a reliever, Duffey didn’t see much improvement, pitching primarily in a mop up role.

 

Tyler Duffey started this season in Triple-A Rochester and was lights out for the Red Wings. Before his call-up to the Twins, Duffey made seven relief appearances, throwing 13 and 2/3 innings while giving up just two runs on eight hits and five walks. What was noticeably different with Duffey, was the rate at which he was striking out opposing hitters. In his career, prior to 2019, Duffey was only striking out 7.8 hitters per nine innings, between both the minor and major leagues. In those 13 and 2/3 innings in Rochester, Duffey struck out 22 opposing hitters.

 

After he got called up to the Majors on April 16th, Duffey continued his great start to the season. So far, in 22 and 2/3 innings for the Twins, Duffey has a 1.99 ERA and has struck out 32 hitters with just six walks. Duffey has held opposing hitters to a .220 batting average and just a .280 wOBA. However, according to Statcast, Duffey’s numbers should be even better, as he has an expected batting average of .193 and an expected wOBA of .251. For context, among the 355 pitchers who have faced at least 100 batters this season, Duffey ranks 27th in expected batting average and 19th in expected wOBA, leading all Twins pitchers in both categories.

 

There are a few of factors that have helped Tyler Duffey become an entirely different pitcher in 2019, than he was in prior seasons. The first, and most substantial factor, is his fastball. Previously, Duffey featured an even mix with both his four-seamer and his sinker, having thrown them 29 and 27 percent of the time respectively. In 2019, Duffey has all but ditched his sinker in favor of his four-seamer. Duffey is now throwing his four-seamer 54 percent of the time, compared to his sinker which he throws three percent of time. This goes a long way towards explaining Duffey’s jump in strikeout rate, as he has a 20 percent whiff rate in his career with his four-seamer, compared to just an 11 percent career whiff rate with his sinker. Another thing that has helped Duffey improve with his fastball is his uptick in velocity. The chart below shows Tyler Duffey’s average velocity on his four-seamer throughout his career.

 

Download attachment: Tyler Duffey average fastball velo.png

 

(Chart via Baseball Savant)

 

From this chart we see that Tyler Duffey's fastball velocity spiked when the Twins transitioned him to the bullpen in 2017, but even after that move, Duffey has continued to add velocity as he has matured. Now at age 28, Duffey has matured physically to the point where he should be throwing his fastball harder than he ever has before.

 

In addition to his change in repertoire with his fastball, he has also mixed things up with his breaking ball. In the early part of his career, Duffey exclusively threw a curveball when he threw a breaking pitch and threw it on 37 percent of his pitches in total. In 2018, he started experimenting with a slider, which he threw seven percent of the time last year. This year his slider has become a much bigger part of his pitching arsenal as he is throwing it 25 percent of the time, compared to just 18 percent of the time with his curveball. This has been a big improvement as Duffey is allowing opposing hitters to hit a .148 batting average and a .193 wOBA against his slider, compared to the .254 batting average and .283 wOBA he has allowed with his curveball in his career. A big part of that can also be explained by Duffey’s whiff rates with the two pitches. So far this year, opposing hitters have a 55 percent whiff rate against his slider, compared to a career 32 percent whiff rate against his curveball.

 

Another big factor that has played into Tyler Duffey’s success this season is his improved command with his pitches. Looking at Duffey’s walk rate, it might not be as apparent because, at six percent in 2019, Duffey is right in line with his career norms. However, when you look at a heat map of where Duffey is throwing his pitches in 2019, it is telling a different story. The below charts show Duffey’s pitch heat map in each of his five season in the big leagues.

Download attachment: Tyler Duffey Strikezone Heatmap.PNG

Download attachment: Tyler Duffey 2019 Strikezone Heatmap.png

 

(Chart via Baseball Savant)

 

You can see from the first four seasons of Duffey’s career, he was primarily pitching in the heart of the zone, and opposing hitters were teeing off on him. This year, Duffey is locating around the edges of the strike zone with his pitches a lot more often. In the 2019 heat map, we can see a spot starting to form down and away from right-handed hitters because he is locating there with his slider quite a bit. This is the ideal location to throw a slider, as it appears that it will be a strike, and then ends out of the zone, enticing hitters to swing and miss at the pitch at a much higher rate.

 

As we can clearly see, Tyler Duffey is not the same pitcher that he was prior to 2018, and he has developed into one of the most effective relievers, in not only the Twins bullpen, but in all of Major League Baseball in 2019. With the Twins in dire need of some more support at the back end of the bullpen, it is time for Rocco Baldelli to start giving Tyler Duffey more opportunities in high leverage situations.

 

Click here to view the article

[diehardtwinsfan]

I want them to still trade for a couple guys, but if they can get Duffy and hopefully one more to someone we could rely on late innings, the pen goes from a weakness to a strength.

[USAFChief]

I don't trust Tyler Duffey and probably never will. On nights when everything is working, he's effective. Those nights aren't frequent enough, IMO.

 

To quote myself semi-quoting our old friend Denny Green, from a game thread back there somewhere..."He is who we thought he was."

 

 

[MMMordabito]

No, it isn't.

[a-wan]

 

I don't trust Tyler Duffey and probably never will. On nights when everything is working, he's effective. Those nights aren't frequent enough, IMO.

 

To quote myself semi-quoting our old friend Denny Green, from a game thread back there somewhere..."He is who we thought he was."

 

 

This. His K% this is great, yet, I still cringe when he pitches. Same with May and his inability to throw strikes.

[yarnivek1972]

Trust might be too strong a word. I’ll go with “try” in high leverage spots. He’s next up I guess.

[bighat]

 

I don't trust Tyler Duffey and probably never will. On nights when everything is working, he's effective. Those nights aren't frequent enough, IMO.

 

To quote myself semi-quoting our old friend Denny Green, from a game thread back there somewhere..."He is who we thought he was."

 

Completely agree. This article reminds me of all the Trevor May hype that seems to come along every spring.

 

May, Duffey, Morin, Magill, etc - these are just "serviceable" guys. The only reason to like Duffey right now is that he's pitching like an average relief pitcher and not getting shelled. But let's not crown him the next Josh Hader just because he's put together a couple of scoreless outings.

 

As one AL Scout recently said about the Twins bullpen: "They have got guys, just like everybody else has guys, just not consistent guys".

 

When you're hungry and you've got no food in the house, all of a sudden that old can of refried beans in the back of the cupboard looks like a suitable meal. It's got some protein and if you're drunk enough it'll taste just fine with some stale tortilla chips and that half-empty bottle of cheeze whiz. Just be careful you don't get that meal confused with the Butterknife Steak at Murray's.

[Riverbrian]

They gotta trust someone.

[wabene]

Duffy has looked good. We've all seem him implode as well. When do we start to trust guys like him and Gibby and May for that matter guys who seem to get rattled? I guess they have a chance of gaining confidence and fortitude. Time will tell but with his stuff I do think they should give him a chance.

[Monticore]

Give him a chance. Why did they ever trade Pressley?!

[Aerodeliria]

In a sense, we have to trust him or someone else because they cannot survive on Harper, then Rogers because as we have seen, they also start to wear down. As for Duffey, I trust him more than I trust Parker or the M & M's, so he's the next iteration, I suppose. The simple solution is to get more bullpen help--not retreads but real live heroes.

[jimbo92107]

 

I don't trust Tyler Duffey and probably never will. On nights when everything is working, he's effective. Those nights aren't frequent enough, IMO.

 

To quote myself semi-quoting our old friend Denny Green, from a game thread back there somewhere..."He is who we thought he was."

I was starting to feel that way myself, until I saw the same kinds of changes in Duffey's stuff that we have seen in Martin Perez. I think Wes Johnson truly is the arm whisperer. He is transforming pitchers in the Twins system, making many of them more powerful and effective. Tyler Duffey used to have a barely adequate fast ball, combined with a mind-bending curve. Now, Duffey has become a power pitcher with an effective 4-seam heater, a really good slider, and still has his big curve. That's quite a change. 

 

Don't forget, we have also seen the velocity increase for Zack Littell, whose heater used to limp in at about 91 mph. Now he pops it in at a brisk 94 to 96. Johnson's magic may not be enough to save every pitcher, but I say give him a full season to see what his nu-wave mechanics can do for all the arms on this team. 

[Vanimal46]

They gotta trust someone.

They do... But that someone doesn't have to be in the organization right now. I would trust almost all of the trade candidates highlighted on this website over the last few weeks instead of Duffey, Magill, Morin, etc.

[Riverbrian]

 

They do... But that someone doesn't have to be in the organization right now. I would trust almost all of the trade candidates highlighted on this website over the last few weeks instead of Duffey, Magill, Morin, etc.

 

I was just listening to George Thorogood covering Bo Diddley's "Who do you Love?" 

 

At no point in the song do they mention Magill or Morin. 

[scottz]

 

I don't trust Tyler Duffey and probably never will. On nights when everything is working, he's effective. Those nights aren't frequent enough, IMO.

 

The good thing about frequency is that it can easily be calculated. Here's the number of times Duffey has given up one or more earned runs in his 2019 appearances, and the rest of the most often used relievers.

 

Name - # of times giving up 1 or more ER out of # of appearances (percentage):

 

May - 5 out of 32 (15.6%)

Duffey - 3 out of 18 (16.7%)

Morin - 3 out of 17 (17.6%)

Harper - 6 out of 33 (18.2%)

Magill - 5 out of 21 (23.8%)

Rogers - 7 out of 29 (24.1%)

Parker - 7 out of 28 (25.0%)

 

I know it is a simple analysis (obviously, he's been in lower leverage situations), but for frequency of effectiveness (assuming no earned runs means he was effective)? He's not an outlier in any negative sense.

 

Note: edited to add "2019"

[lecroy24fan]

Duffey was up in the pen behind Parker in the ninth yesterday so i think he has that trust right now. 

[Mr. Brooks]

Completely agree. This article reminds me of all the Trevor May hype that seems to come along every spring.

 

May, Duffey, Morin, Magill, etc - these are just "serviceable" guys. The only reason to like Duffey right now is that he's pitching like an average relief pitcher and not getting shelled. But let's not crown him the next Josh Hader just because he's put together a couple of scoreless outings.

 

As one AL Scout recently said about the Twins bullpen: "They have got guys, just like everybody else has guys, just not consistent guys".

 

When you're hungry and you've got no food in the house, all of a sudden that old can of refried beans in the back of the cupboard looks like a suitable meal. It's got some protein and if you're drunk enough it'll taste just fine with some stale tortilla chips and that half-empty bottle of cheeze whiz. Just be careful you don't get that meal confused with the Butterknife Steak at Murray's.

He's pitching far better than an "average" reliever right now though. Did you read the article?

[the_brute_squad]

I agree that it's time to start trusting him. The Twins have moved a few average to less than average starters into the bullpen and they became all - stars. Notably Aggie, Hawkins, and Perkins. I'm not saying Duffy will be in that class, but he's showing his stuff is pretty good and if he has the right mentality he could be the bullpen stud the Twins need.

[ashbury]

I think this article is a little behind the times. Duffey's three highest-leverage appearances have all been in the month of June. Two successes, one fail IMO (whether or not the runs counted as earned). 21 batters faced in those 3 games, 12 outs recorded. Jury's out, I'd say, but it's not been stellar.

 

His OPS is better than league average, and for relievers I find that a simpler way to assess results than to pick through unearned runs and inherited runners and so forth. I guess the braintrust noticed too, and decided to start testing him a little more when it matters, about three weeks ago.

[Andrew Thares]

 

I think this article is a little behind the times. Duffey's three highest-leverage appearances have all been in the month of June. Two successes, one fail IMO (whether or not the runs counted as earned). 21 batters faced in those 3 games, 12 outs recorded. Jury's out, I'd say, but it's not been stellar.

 

His OPS is better than league average, and for relievers I find that a simpler way to assess results than to pick through unearned runs and inherited runners and so forth. I guess the braintrust noticed too, and decided to start testing him a little more when it matters, about three weeks ago.

Has Duffey gotten a few high leverage appearances this month? Yes. But let's break down these appearances real quick.

 

The most recent one was the 17 inning Red Sox game. Literally all 8 of the pitchers in the Twins bullpen pitched in a high leverage situation in this game, and Duffey only got in after Rogers, May and Harper had already been used.

 

Another one was the Mariners game on June 12th, where the Twins had already turned to Morin, May and Parker in important spots before they went to Duffey. Also Rogers was unavailable due to his back issue.

 

The other high leverage spot was on June 7th against Detroit. A game in which both Rogers and May were unavailable due to high pitch counts in the previous two days. So the Twins had to turn to Morin, Harper, Duffey and Parker for high leverage innings in this game.

 

The rest of Duffey's outings have been in very low leverage spots when the Twins were down by a few runs, or had a huge lead.

 

To me it looks like Duffey has only been used in high leverage spots out of necessity, and not because the Twins actually wanted him pitching there.

[In My La Z boy]

We'll know we have a solid bullpen when Duffy and May are the 6th and 7th options. Like Pineda - who makes a decent #5 - but would be a poor #2 or #3.
We'll know we have a solid bullpen when we stop discussing Duffy or May for high leverage roles. They are decent bullpen fillers. That's it.
Its become obvious the front office did not anticipate being buyers this year and being this good. If they knew we'd be this good, Ryan Pressly would be our closer. We'd have never flipped him for some future magic beans. Never. Front office malpractice if they had any clue we'd be in this thing in 2019.