Ben Ruppert investigates Week 4 trends in Starting Pitcher strikeout rates (K%). These MLB risers and fallers present buying and selling opportunities for your fantasy baseball team.

We’re constantly trying to come up with new features that will help you dominate your fantasy leagues. Last year we built a tool that identifies the biggest trends in a pitcher's strikeout rate over the last thirty days.  The tool is for Premium subscribers only, and can be found here. With our sample size being so small this early in the season though, we will look at the difference between pitchers' final 2016 K-Rate and their current K-Rate through two to three starts.

Missing bats is the #1 way a pitcher can control his own fate. If hitters make contact, the pitcher is largely at the mercy of the atmosphere, the weather, the ball park, the ability/work ethic of his fielders, and sometimes just sheer luck. This is ultimately why strikeouts are so important.  By looking at pitchers with positive trends in their strikeout rate, we can spot improving or declining pitchers. If the K-rate is improving, but the ERA and WHIP are less than ideal, it can present a buying opportunity. On the flip side, you may want to sell a pitcher with a declining K-rate, if he wasn't supposed to be that good to begin with.

This particular article will focus on two strikeout rate risers and two fallers, and make an attempt to determine how you should treat each pitcher.

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K-Rate Risers

Dan Straily, Miami Marlins

2016 K-Rate: 20.5%, 2017 K-Rate: 28.9%

The 2016 season was a huge revival season for Dan Straily. In 2015, he pitched mostly in the minors with the Astros, and knew a change needed to be made. In his first and only season with the Reds he threw 191 1/3 innings over 34 appearances (31 starts), with a 3.92 ERA and 1.06 WHIP. He won 14 games, and notched 20 quality starts which placed him in the top-20 among all starters. He picked up right where he left off this season, with a 3.92 ERA after four starts and a 10.45 K/9 rate. His last start was an impressive seven-inning, 14 strikeout performance.

Straily credits his career revival to Driveline Baseball, a data-driven baseball performance startup that has worked with him the past two offseasons. He worked on building up his shoulder strength by using weighted baseballs, which has not only helped his velocity but also has shortened the recovery period in between starts. You may be skeptical, but looking at how Straily has pitched the program seems to be doing wonders for his career. While his .217 BABIP may suggest he has gotten a bit lucky this season, his FIP/xFIP of 3.99/3.74 support his current ERA. His swinging strike rate (SwStr%) is at a career-high 12.2% right now, and his contact rate is at its lowest point since 2014.

His career average for K/9 is 7.68, so while I don’t believe in his big K/9 jump I do believe he will be an effective fantasy pitcher this season. I am not buying his rising strikeout rate, but if you’re looking for a pitcher who can rack up quality starts Straily can be had for cheap and be a solid back-end pitcher.

Verdict: Buy

Wade Miley, Baltimore Orioles

2016 K-Rate:19.3%, 2017 K-Rate: 31.4%

Wade Miley has been a workhorse since 2012, averaging 31 starts and 192 innings pitched per season. The innings are great, but the career 4.13 ERA and 1.34 WHIP make fantasy owners want to look in another direction. However, ever since he got to Baltimore he’s been putting up some improved numbers. He made 11 starts with the O’s after being traded from the Mariners, and although he put up a 6.17 ERA his BABIP was at .389 (career .306 BABIP) and his FIP/xFIP were 3.79/3.34 which suggest he got very unlucky.

This season the exact opposite has happened. His FIP/xFIP are in the same range at 3.24/3.36, but his BABIP is down to .189 and his ERA is at 2.08. It is surprising his WHIP is 1.00, considering he is walking 4.85 hitters per nine innings this season. After posting a 9.17 K/9 after the trade last season (career 7.16 K/9), that rate is up to 11.08 this season. He has held hitters to a .138 batting average against, and has increased his soft contact rate to a career-high 20.0%. His contact rates and SwStr% are all in line with his career norms, and his pitch velocities/movements are all similar, so this seems like simply a hot stretch of games for the veteran arm.

He has pitched better in Baltimore, but nothing in his profile suggests any changes in his approach. Enjoy Miley while he’s pitching well, but there is definitely going to be some regression here. He has shown in the past he can pitch 200 innings with a sub-4.00 ERA, so he still does have value, but I would be looking to sell high.

Verdict: Sell

K-Rate Fallers

Danny Duffy, Kansas City Royals

2016 K-Rate: 25.7%, 2017 K-Rate: 18.6%

After beginning last season in the bullpen, Danny Duffy impressed enough to regain a spot in the starting rotation. He was extremely impressive until late in the season, when he faltered down the stretch likely due to fatigue after throwing a career-high 179 2/3 innings. If you remove his September starts, he held a 3.01 ERA, 1.03 WHIP, and an elite 4.92 K/BB ratio over 125 2/3 innings. The strikeouts and elite control are things we hadn’t seen from Duffy in the majors until last season, though his minor league stats show he always had that in him somewhere.

Expectations were high for Duffy heading into this season, and while his current 2.81 ERA is great there are some underlying concerns. His strikeout and walk rates have gone back to his pre-2016 rates; his K/9 is down to 6.75 and his BB/9 are up to 3.38. His BABIP is in line with his career norm, and hitters are hitting him just as well as last season. Right now Duffy just isn’t missing as many bats, though he is generating more ground balls than last season. This may be due to his pitch selection, and the loss of velocity on his fastball. He has lost nearly two MPH on his heater, which still averages 93 MPH on the gun. He is throwing his slider and changeup at a much higher rate this season, and both have done well with SwStr% of 18.3% and 16.8% respectively. He just isn’t blowing the heater past hitters like he was last season.

Duffy is certainly a different pitcher now than we saw last season. His velocity is down, his breaking pitches are getting more use, and we have had mixed results in the early goings. I think Duffy will be a good pitcher this season, but won’t provide the strikeouts fantasy owners drafted him for. If I could sell him for an ace right now, I would be looking into it.

Verdict: Sell

Kevin Gausman, Baltimore Orioles

2016 K-Rate: 23.0%, 2017 K-Rate: 14.2%

You wouldn’t have thought Baltimore’s opening day starter would be the problem in the rotation a month in, but here we are. Last season he posted a 3.61 ERA, 1.28 WHIP, and struck out 8.72 hitters per nine. He was pegged as a breakout candidate in fantasy circles; however his first month of the season has been poor to put it lightly. Through his first five starts, Gausman is averaging less than five innings per start with a 7.50 ERA and 2.04 WHIP. His strikeouts are down and his walk rate is way up, leaving him with an awful 1.13 K/BB ratio. Even his FIP/xFIP don’t paint much of an improved picture at 5.72/5.57 respectively.

So what’s been going wrong with Gausman, and can he correct it? His pitch usage is the same as last season, as are his velocities and movements. This season his splitter, which was arguably his best pitch last season, is getting hit hard and often. Opposing hitters have hit .407 against it this season after hitting only .203 against it last season. His slider has also seen a spike in batting average against, while his fastball has remained similar. Point being, hitters are waiting on his 99 MPH heaters to zip by while they sit on his breaking stuff. Coming through the Baltimore system he was known for his heater, but did not have a strong repertoire of secondary pitches. Left-handed hitters hit only .231/.272/.387 off of him last season, and are now hitting .350/.447/.475 against him this season.

His stuff is noticeably off right now, but it seems like this is more of a poor stretch than an extremely large step back for the young pitcher. Right now Gausman is the definition of a buy-low pitcher. Better times are ahead for him, though it remains to be seen how long this funk lasts. Buy him now if you can afford to stash him while he figures it out.

Verdict: Buy

More Risers and Fallers