Strikeout Rate Risers and Fallers - Buy or Sell for Week 6

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.

This is the first week that we will be 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%.

The season isn't much longer than 30 days to this point, so the tool will provide deeper insight as the season progresses. That being said, this is still a great tool for identifying potential buy-high and sell-low candidates.

Strikeout Rate Risers

All stats current as of Sunday, May 5

Sonny Gray - Cincinnati Reds

Season K%: 27%, Last 30 Days: 30.9%

Our first K% riser is one who not only has seen a strikeout improvement in the last 30 days but an overall improvement from last season. Sonny Gray had an up-and-down tenure with the Yankees but seems to be thriving in his new home in Cincinnati. The 29-year-old has a respectable 3.89 ERA and 1.04 WHIP with an impressive 27% K rate and an even higher 30.9% in his last 30 days. Coming off a poor 2018 season, should you buy what he's done so far?

Gray has had several strong fantasy seasons in his career, so it should not be surprising to fantasy players that he can bring value to their teams. Gray has been able to induce ground balls (7.6-degree launch angle) as he has done in the past, but has changed his pitch mix a bit. Gray has relied more on his straight fastball (40.4%) than his sinker (16.5%). This switch has been a good one, as he has a career-high swinging-strike rate of 9.8% with the pitch compared to a 6.4% mark with his sinker in 2018.

Grays new change of scenery may also be helping him pitch well. New York is the biggest of stages with unforgiving fans and many athletes have crumbled under the pressure of performing there. A move out of that spotlight may have been what Gray needed to relax and get back to form. The move also brought a reunion with Gray’s college pitching coach, Derek Johnson, which is a positive thing. Overall, it is hard to find a ton of changes in Gray’s game, but he has been a solid fantasy pitcher before and is showing signs of it again. I am buying into Gray's relative success and consider him to be a buy-low candidate/waiver-wire claim.

Chris Sale - Boston Red Sox

Season K%: 26.9%, Last 30 Days: 32.5%

I wrote about our second K% pitcher earlier in the season as a worrisome K% faller. Chris Sale has been one of fantasy's top strikeout pitchers for many seasons now, so it should not be a surprise to see him as a riser. However, given that he started the season dreadfully and has a 5.25 ERA through 36 innings pitched, it is worth providing a closer look into his last three starts to see what has changed.

Sale's first four starts yielded a bloated 8.50 ERA with just 14 strikeouts in 17 IP. However, his last three starts look like the Chris Sale of old, with a 2.00 ERA and 28 strikeouts in 18 IP. Sale has been getting much better results lately, but the issues that surrounded him at the beginning of the season still remain. His fastball sits at an average of 92.5 MPH compared to 95.2 MPH last season, which may have to do with the shoulder injuries he suffered.

He is actually throwing his slider primarily over his fastball to this point (42.1% usage vs 31.6%), and while his slider is a great pitch (14.4% swinging-strike rate) it hasn't been as effective of a strikeout weapon as it was in 2018 (18.1%). Overall, Sale is trending in the right direction and is looking more like a top fantasy pitcher, but I fear that he may have to reinvent himself slightly to be effective and that his decreased velocity may eventually hurt his strikeout numbers. I buy that he is a solid fantasy pitcher but sell that he will be as effective as he has been in seasons past.

Strikeout Rate Fallers

All stats current as of Sunday, April 21

Matthew Boyd - Detroit Tigers

Season K%: 32%, Last 30 Days: 26.2%

Matthew Boyd got off to a huge surprise start this season and received a lot of attention in the fantasy community. I myself wrote about him as a strikeout rate riser and wasn't ready to buy into him then. However, Boyd has continued to excel, posting a 3.05 ERA with a 32% strikeout rate. His strikeout rate in the last 30 days has fallen a bit, so is he starting to fall off?

The short answer is no. This is a case of a small sample size greatly affecting the premium tool. Boyd has had three Ks, nine Ks, and nine Ks in his last three starts. The three-K outing is pulling his totals down because he has only made seven starts. Despite the low punchouts in the one start, Boyd was great in those starts, compiling a 3.15 ERA with two wins. Fantasy owners should not be worried about his K% at this point even though his stat appears to have fallen off.

Despite his great start, I am still not totally ready to buy into Boyd. His 3.13 SIERA and 15% swinging-strike rate support his strong peripherals, although his career marks are 4.43 and 10%, respectively, so some regression would not be surprising. Further, he relies heavily on a mediocre fastball in terms of velocity (50.2% usage with 90.9 MPH average velocity). Finally, his 19.6-degree launch angle and 30.2% hard-hit rate do not jive with the fact that he has only allowed two home runs. At this point, Boyd owners could continue to ride out his success or attempt to sell high on him.

Jacob deGrom - New York Mets

Season K%: 34.8%, Last 30 Days: 26.9%

Our second faller was one of baseball's most-highly touted fantasy starters for the 2019 season but has had an up-and-down start. Jacob deGrom carries a pedestrian 3.82 ERA through 33 IP, and while his season K% is a great 34.8%, his mark has fallen considerably in the last 30 days. What should fantasy owners make of deGrom's first six starts?

deGrom's arsenal is as strong as ever. He is throwing his slider (92.6 MPH vs 91.1 in 2018) and fastball (96.5 MPH vs 95 MPH) harder, and while his strikeout rates are higher on both pitches, his swinging-strike rates (a better indicator of the overall effectiveness of the pitch) are down on both pitches.

Breaking down his starts further, deGrom has three starts with no earned runs combined, and three with 14 total earned runs allowed and five home runs. These sets of starts are so polar opposite that it may be hard to decide what to make of deGrom overall. Ultimately, his pitch arsenal looks good, the strikeouts are there, his control has been decent (1.24 WHIP) and his 3.13 SIERA suggests that he has pitched better than his ERA indicates. deGrom is a high caliber fantasy player and should be given a longer leash. I would consider him to be a buy-low candidate for any owners who are scared about his poor start set.

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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