Strikeout Rate Risers and Fallers - Buy or Sell for Week 20

Welcome back to the strikeout rate risers and fallers series for Week 20! 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%.

As we approach the fantasy playoffs, it is now more important than ever to pay attention to how players on your teams are trending. Every start counts, so choosing whether or not to send a pitcher out or keep them on your bench is key. Let's take a look at two starters who have been better in terms of strikeouts and two who have been worse.

Strikeout Rate Risers

All stats current as of Sunday, August 11

Jack Flaherty - St. Louis Cardinals

Season K%: 28.6%, Last 30 Days: 36.1%

Our first K rate riser started the season as a promising young starter yet did not provide what owners were hoping for. However, Jack Flaherty has rebounded and now owns a 3.72 ERA, 1.13 WHIP, and an impressive 28.6% K rate on the season. He has done even better lately, bumping that mark to a sterling 36.1% over the last 30 days. How has Flaherty done it and can we expect more of the same from him?

Simply put, Flaherty has been pitched out of his mind his last five starts. He has put up a minuscule 0.86 ERA and 0.83 WHIP with at least seven strikeouts per start. He faced some tough matchups as well, including the Astros, Cubs, and Dodgers. Flaherty relied on his fastball-slider combo to get his strikeouts, much as he has throughout the season. He has a decent fastball at 94 MPH with a 9.4% swinging-strike rate and a filthy slider with a 24.4% swinging-strike rate.  

Flaherty has shown that he can be a solid fantasy pitcher and this has been especially true in his last five starts. It is unlikely that he can continue to pitch at that level, but he will be a key fantasy contributor down the stretch even if he regresses towards his season averages.   

Jeff Samardzija - San Francisco Giants

Season K%: 20.8%, Last 30 Days: 26.1%

Our second K rate riser has been a fantasy staple in the past and seems to be reliving his glory days. Jeff Samardzija has compiled a 3.55 ERA, 1.11 WHIP, and 20.8% K rate this season and has managed a 26.1% K rate over the last 30 days. Could Samardzija be a stealthy fantasy stud down the stretch?    

Samardzija's numbers over the last 30 days look great on the surface; he has posted a 2.27 ERA and a 0.84 WHIP. The strikeouts have also been up, of course, thanks mostly to a nine-strikeout game at the Rockies and a seven-strikeout game against the Mets.

However, things don't look quite as good under the hood. For one, Shark's strikeout numbers haven't been all that impressive this season due to the fact that he relies mostly on pedestrian fastball variants. Further, his .190 BABIP in his last six games is much lower than his .291 career mark, suggesting negative regression could be on the way. Further, his 4.04 SIERA over those games suggests that he significantly outperformed himself with a 2.27 ERA.

Samardzija has actually been a useful fantasy option again this season, particularly of late, but underlying signs indicate he may not be quite as useful for the rest of the season. Many metrics suggest that he has been outperforming himself and has had luck on his side. Should he indeed regress, he could still be a useful back-end starter in favorable matchups, but I would not feel comfortable starting him in every matchup for the rest of the season.

Strikeout Rate Fallers

All stats current as of Sunday, August 11

Jon Gray - Colorado Rockies

Season K%: 23.5%, Last 30 Days: 18.7%

Our first K rate faller has had an ok season overall after struggling early. Jon Gray was thought to be a fantasy miracle a few seasons ago, cracking the Coors Field code. While he hasn't quite done that, his 4.06 ERA and 23.5% K rate are respectable. However, he has managed just an 18.7% K rate over his last 30 days. Let's take a look at Gray and see if there is anything to worry about.

Nothing really stands out in terms of Gray's performance over the last 30 days. He is a mediocre pitcher who has turned in mediocre results. Gray has posted a 4.50 ERA and 1.44 WHIP in his last six starts, which line up with his 1.39 WHIP and 4.41 SIERA on the season. He brings the heat with his fastball (96.1 MPHH), which helps set up his slider and curveball, but his K rate isn't more impressive because of his lack of control. His K rate is down compared to normal, but the fluctuation is not shocking given his control of late.

Gray is one of those fantasy players who will frustrate you all season long, giving you glimpses of excellence as well as stretches of poor numbers. His home field and lack of control prevent him from providing consistent results. I would not want to have to rely on him with a fantasy playoff spot on the line.

Madison Bumgarner - San Francisco Giants

Season K%: 23.5%, Last 30 Days: 19.5%

Our second K rate faller is a veteran who has been a fantasy staple for many seasons and is still getting it done. Madison Bumgarner has been solid for the Giants this season, compiling a 3.74 ERA, 1.13 WHIP, and 23.5% K rate. However, his K rate has fallen over the past 30 days. Is this something that fantasy owners should be worried about?

I will quickly reassure owners that there is nothing to worry about. MadBum has a 2.93 ERA and 0.95 WHIP over his last six starts, including a one-hitter seven-inning performance against the Phillies in his last start. His strikeout numbers have been down a bit, but fantasy owners won't complain as long as he pitches to his standards. The one thing to note is his lackluster 4.64 SIERA, but Bumgarner has been outperforming his batted-ball profile all season, thanks in part to his pitcher-friendly Oracle Park.

Bumgarner has been one of the game's top clutch pitchers for seasons now and there is no reason to think that won't continue. He has continued to pitch well overall, which fantasy owners have come to expect.

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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