Strikeout Rate Risers and Fallers - Buy or Sell for Week 9

Welcome back to the pitching strikeout rate risers and fallers article series! Each week we will take a look at two K% risers and two fallers, analyze what is behind those changes, and then decide if they are actionable. A pitcher can best control their fate by generating swings and misses, so this exercise holds particular importance for fantasy value. Understanding strikeout trends and the stats behind them can help you sort through all the noise and determine which pitchers are legit and which pitchers should be avoided.

The players in this article were chosen using RotoBaller’s K% Risers and Fallers premium Tool. This tool identifies players who are surging and falling in strikeout percentage over the last 30 days. The goal of this tool is to help you find pitchers who are showing improving or declining K%.

We now have two month's worth of data at our disposal, so the tool can be used at its full capacity! Let's get into it and see what insights we can draw on our K% risers and fallers.

Strikeout Rate Risers

All stats current as of Sunday, May 26

Mike Minor - Texas Rangers

Season K%: 25.5%, Last 30 Days: 30.3%

Our first K% riser is a veteran who has always been a decent fantasy option but never a great one. That is, until this season. Mike Minor has performed extremely well in 2019 despite pitching his home games in hitter-friendly Globe Life Park, posting a 5-3 record with a 2.5r ERA, 1.13 WHIP, and an impressive 25.5% K rate. He's done even better in the past 30 days with an impressive 30.3% K rate, so has the 31-year-old made a legit change in his game?  

Several things stand out regarding Minor's bump in K% over the last 30 days. First, he has taken advantage of some favorable matchups. In his past six games, Minor has a nine-strikeout, 11-strikeout, and 13-strikeout performance. Two of those games came against the Mariners, who have the most strikeouts as a team in the Majors, and the third came against the Blue Jays, who are tied for the sixth-most. This is not to take away from Minor's performances, but based on his career K rate of 21.7%, it seems that he happened to bring his A game in favorable situations.

The second thing that stands out is Minor's effective secondary pitches. His fastball, while not overpowering at 92.9 MPH, has one of the highest spin rates in the league at 2,648 revolutions per minute, making it an especially deceptive pitch. Further, Minor has been relying on his slider and changeup more lately to mix things up, and they have been effective. His 14.8% K% on his changeup is actually down from his career 15.6% mark, but his 13.4% on his slider is a career-high for the pitch.

It looks like Minor, while he has been pitching very well, has not really made any significant changes to his game in terms of his strikeout potential. He has taken advantage of some great matchups lately, which has boosted his perceived fantasy value. His 2.55 ERA is much lower than his 4.0 SIERA, making him a good sell-high candidate. However, fantasy owners should only part with him if they can get a good deal, as he has been a fantasy steal to this point.

Shane Bieber - Cleveland Indians

Season K%: 30.6%, Last 30 Days: 33.8%

Our second K% riser has been very impressive this season, especially in terms of strikeouts. 23-year-old Shane Bieber is in just his second big-league season but has a stellar 3.11 ERA, 1.05 WHIP, and 30.6% K rate in 63 2/3 inning pitched. His season K rate has been impressive and it has been even better over the past 30 days. Has Bieber already figured things out at the big-league level?

Bieber has some conflicting signs in terms of his overall performance. His arsenal in itself isn't great; his fastball sits at 93.2 MPH and his slider and curveball don't have a ton on spin on them. That being said, Beiber has been mixing his pitches more over the past 30 days, relying less on his fastball and mixing in his offspeed pitches more. His K rate on his fastball is a poor 4.3%, but his curveball mark is an impressive 27% and his slider mark is 23.2%. The fastball is very concerning, but his offspeed pitches have been working to this point.

While Bieber's K% is impressive, his batted-ball profile is not. He has gotten hit quite hard this season (90.6-MPH exit velocity, 46.9% hard-hit rate, 14.2-degree launch angle) yet has not seen the negative effects to this point. His 3.32 SIERA suggests that there is nothing to worry about, but his .267 BABIP is much lower than his .356 mark last season.

Overall, Bieber is a tough case to figure out. He has had great success with his offspeed pitches but his fastball is pedestrian at best. He has gotten hit hard but has posted great numbers that are somewhat supported, somewhat not. I'm not ready to totally buy into Bieber yet, but as he is just 23, he is certainly valuable in dynasty leagues and is worth holding onto in single-season leagues until things become a little more clear.

Strikeout Rate Fallers

All stats current as of Sunday, May 26

Trevor Bauer - Cleveland Indians

Season K%: 27.2%, Last 30 Days: 23%

Our first K% faller came into the season as a highly-touted fantasy option but has been merely pedestrian to this point. Trevor Bauer received a lot of attention in 2018 for his performance on the field and his antics off the field/online. However, his 4.11 ERA and 11.9% walk rate have been a significant step backward towards the mediocre Trevor Bauer of old. His 27.2% K% on the season is respectable, but his 23% mark in the last 30 days is just another stat trending in the wrong direction. Should fantasy owners be panicking?

There is one standout facet of Bauer's game that could help explain his decrease in strikeouts and overall performance; his lack of command. His 11.9% walk rate is a good deal higher than his 8% mark from last season and his mark over the last 30 days has inflated to 13.3%. Bauer's 1.34 WHIP in that timeframe is also higher than his 1.17 on the season and 1.09 in 2018. Bauer's pitches are all similar in terms of velocity and spin rate to what they were last year, but his inability to command them has resulted in both a decrease in strikeouts as well as an increase in runs scored.

The reality regarding Bauer is that, prior to 2018, he had never posted an ERA lower than the low 4's or a WHIP lower than 1.31. Strikeouts are of course important for fantasy and Bauer has a respectable career 24.3% K rate, but he has never been a dominant fantasy ace other than 2018. Perhaps last season was his career season, but I would not be surprised to see Bauer end the season with numbers similar to what he has now.

Jack Flaherty - St. Louis Cardinals

Season K%: 25.8%, Last 30 Days: 21.7%

Our second faller came onto the fantasy last season with a strong rookie performance and is doing a decent job following that up in 2019. 23-year-old Jack Flaherty has compiled a 3.77 ERA, 1.25 WHIP, and 25.8% K rate over 59 2/3 IP this season and looks like a legit fantasy asset. His K rate has fallen over the past 30 days, but he has still pitched well in that time. Let's take a deeper look at how Flaherty has found success this season.

Flaherty has already developed a pretty effective arsenal of pitches. His fastball has some giddyup on it at 94 MPH and has a respectable 10.3% swinging-strike rate and his slider, his primary secondary pitch, has been an effective complement, averaging 84.6 MPH with an impressive 22.3% swinging-strike rate. His curveball is not quite as developed as his first two pitches but he has a decent sinker, rounding out a nice set of four pitches he relies on. He has also done a nice job limiting hard contact this season (33.6% hard-hit rate, 85.7-MPH exit velocity), thanks to his good control (8.9% walk rate, 1.25 WHIP).

Overall, Flaherty seems like a safe mid-to-back-end fantasy starter. He limits hard contact, gets decent strikeout numbers, and avoids blowup outings. He still has plenty of room to grow at the big-league level, making him a high floor, high upside starter.

K-Rate Risers and Fallers - Premium Tool

Identifying top strikeout rate risers and fallers for each week can help you spot the best pickups before your competition. RotoBaller's Premium K-Rate Risers and Fallers tool has you covered every day. As thoughtful fantasy baseball players, we won't lead you astray. This tool will soon be active once we have a large enough sample size in the season to be considered reliable.

This type of data is available as part of our Premium MLB Subscription. Don't settle for basic stats and surface-level advice from other sites. RotoBaller brings you advanced statistics and professional analysis that you need to win your fantasy leagues and DFS games, because we're ballers just like you. We are your secret weapon!

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