Daniel Stumpf could be the Tigers’ next high-leverage reliever

On July 1, the Detroit Tigers played a doubleheader against the Cleveland Indians. Young lefthander Daniel Stumpf pitched in both games — although he only faced four batters — something that doesn’t happen all that often.

Something else that doesn’t happen very often is a 15-game scoreless streak. There are only 18 pitchers who have done so during the 2017 season, and Stumpf is one of them. In fact, his streak is still currently intact; the last run he allowed was the first game of that July 1 doubleheader.

Stumpf is an interesting story. Only 26 years old, Stumpf had pitched just five major league innings prior to this season. He was originally drafted by the Kansas City Royals in 2012 but never reached the majors. The Philadelphia Phillies acquired him in the Rule 5 draft in the winter of 2015 and he made three appearances before being suspended for failing a drug test. After a few more appearances for Philadelphia, he was returned to Kansas City in July 2016. The Tigers, mimicking the Phillies, drafted Stumpf in the Rule 5 draft in December 2016.

Stumpf was called up in June, — out of desperation by the Tigers, in my opinion — in hopes that he would take off and give the team a solid relief option to support Shane Greene and Justin Wilson after Francisco Rodriguez was removed from the closer’s role. Stumpf struggled from the get-go. He made 12 appearances in June totaling 7 ¹⁄₃ innings. He allowed 10 hits, four runs, three walks and struck out 10. The peripherals looked good, but the results didn’t, and the advanced metrics were just ugly.

Then he started putting up zeroes

It only took Stumpf a couple of weeks for him to settle in, though. Let’s look at how he has performed before and after the start of his scoreless streak.

As good has Stumpf has looked, something doesn’t add up. Before we sound any alarm bells, we have to factor in that we’re dealing with an extremely small sample size.

From the data we have so far, nothing supports that Stumpf is doing anything to aid this scoreless streak. He is relying heavily upon defense and some good fortune to tip-toe out of giving up runs. This isn’t to say that Stumpf can’t be a great back-end reliever. After all, he’s 26 years old, only has 25 major league innings under his belt, and just over 20 more at Triple-A. It’s hard to judge him on what he has shown us thus far.

Here’s why Stumpf is intriguing

Stumpf has three pitches, but relies heavily on just two. He uses a four-seam fastball about 61 percent of the time, and a slider almost 35 percent of the time. He also features a changeup, but uses it only five percent of the time.

His slider has been solid all season, having not surrendered a walk in 22 at-bats while striking out five. The only baserunners that have come via the slider were a hit-by-pitch and three singles. It is ranked 19^th among relievers with at least 20 innings pitched according to FanGraphs’ pitch value per 100 pitches. He is behind superstars such as Kenley Jansen, Roberto Osuna, Greg Holland, Trevor Rosenthal and Felipe Rivero, who rank among the best relievers in several categories across the board. Stumpf’s slider ranks ahead of Shane Greene’s in the same metric, and we all know how good Greene’s slider has been this season.

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However, Stumpf’s four-seamer leaves something to be desired. At times, it has the looks of a solid fastball but it seems like it’s either on or it isn’t. When it’s on, he is almost unhittable. Stump has struck out 12 hitters in 41 at-bats with the four-seamer. When it’s not on, it’s a tee-ball pitch that renders Stumpf almost useless; in those same 41 at-bats, he has allowed nine walks and two home runs.

Further compounding Stumpf’s issues is his changeup. It’s almost non-existent, as he has only thrown 14 of them out of over 300 total pitches. Only two changeups were put into play, resulting in a groundout and a lineout. He seems to be mixing it in a little bit more of late, but it’s still not being used enough for a batter to even think about that pitch. It has swing-and-miss potential, but he needs to get a better feel for it and start using it more often.

There’s room for improvement, though

Stumpf’s main focuses should be to work on the four-seamer and start using the changeup more often. Even if the changeup results in terrible outcomes, he still needs to use it in games in order to get a better feel for it. He can’t solely rely upon a slider to be successful. In order to be a true back-end reliever, he needs at least two pitches that are reliable out pitches.

Even with the red flags Stumpf has shown, I think he is an above average value for several reasons. He’s only 26, a year or two behind when the typical reliever begins his major league career. He is under team control through the 2022 season, and still has minor league options remaining. Most importantly, he has shown flashes at times that he can be a successful back-end reliever. His slider is legitimate; he just needs more innings to build his confidence and work on his other pitches. When you consider the bullpen’s recent history and the Tigers’ pending rebuild, Stumpf should be given the ample time needed to fine-tune his repertoire.

Cheap bullpen arms that can provide reliable innings, if not above-average performance during high leverage appearances, don’t come around often. Even rarer is a reliever with that potential who is under team control for another five seasons. The Tigers have themselves a bargain if they handle Stumpf appropriately and give him time to build some consistency and experience.