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. 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

Nate Karns, Kansas City Royals

Season K-Rate: 28%, Last 30 K-Rate: 34%

Nate Karns has pitched in a different uniform each of the past three seasons, landing on the Royals in 2017. Luckily for them, Karns saved his best strikeout work for this season. For his career he holds a 9.36 K/9, 2.56 K/BB, and a 4.42 ERA. Through seven starts this season he holds a 4.46 ERA, but that comes with a 10.71 K/9 and 3.69 K/BB. Across three May starts he has racked up two quality starts with a 29:4 K:BB.

Karns has been mixing in his changeup more this season, throwing it 5% more than last season at the expense of his fastball. It has held opponents to a .185 batting average against, and induces ground balls at a career-high 61.9% rate. His knuckle-curve has also been extremely impressive this season, generating a 25.6% swinging strike rate (SwStr%) and a .169 BAA. Though his hard contact is up 1.6% this season from last (32% in 2017), he has increased his soft contact to 23% (up 4.3%). Karns has been a victim of the long ball this season with an inflated 19.6% HR/FB rate, after allowing four HR in one game last month against the Rangers. His contact % is the lowest of his career at 72.7%, 10^th best among all starters this season. He also has a healthy 31.6% outside swing %, meaning hitters aren’t making contact because they’re swinging at Karns’ nasty curve, which falls out of the zone generating a ton of strikeouts.

Karns looks legit in a Royals uniform, and I’m buying the improvements I’m seeing from him. He can be a valuable middle of the rotation starter if he keeps up these changes in his approach.

Verdict: Buy

Jake Odorizzi, Tampa Bay Rays

Season K-Rate: 20%, Last 30 K-Rate: 33%

Outside of a hamstring injury that placed him on the disabled list, it’s been an encouraging start to the season for Jake Odorizzi. Through seven starts he has thrown 37 innings with a 3.16 ERA and 0.89 WHIP, making his biggest strides in his walk rates. His BB% went from 7% last season down to 4.9% this season, resulting in him walking nearly a full hitter less per nine innings. For a pitcher who struggled to make it through six innings last inning, this is welcoming news.

Though his pitch selection and velocities remain similar to last season, its easy to see some of the improvements he’s made: he holds a .193 BAA, his hard contact is down from last season, and he holds the highest SwStr% of his career at 11.8%. There is also some cause for concern however. His BABIP is at an unsustainably low .192 right now, which should move closer to his career .274 moving forward. His line drive % is at 27.6%, which is second in the league among starters. He has dropped his hard contact, but his soft contact has fallen as well. He has been able to minimize the damage against him so far, but we could see some regression coming for him soon.

Even if some regression does come, Odorizzi has been able to out-pitch his peripherals each of the past two seasons while holding a mid-3.00 ERA. This may be a good time to sell Odorizzi while his value is at its peak, but if you hold him you’ll have a valuable middle of the rotation arm for the entire season.

Verdict: Sell/Hold

K-Rate Fallers

Luis Severino, New York Yankees

Season K-Rate: 28%, Last 30 K-Rate: 21%

One of the biggest question marks in the Yankees rotation heading into the season was Luis Severino. He’s shown flashes of his potential early in his career, but had been inconsistent in his play. This season he came out blazing with two double-digit strikeout games in his first three starts. His April starts were loaded with strikeouts, but in May we’ve seen some of that inconsistent play pop up again.

In April opposing hitters hit only .175/.208/.309 over 27 innings against Severino, with a 32.7% K%. In 20 May innings, that line rose to .281/.363/.463, with a 22.8% K%. His BB% is also trending in the wrong direction, rising from 4% to 9.8%. What caused these drastic changes? The problem is nothing changed; Severino has just become more predictable and hitters have caught on to his approach. Below you can see the pitch locations for his fastball and slider over the first month of the season, then over his second month.

You can see his pitches have become more centralized, causing his contact % to rise, his SwStr% to fall, and his hard hit % to rise 10%. It is now Severino’s turn to adjust, and if he can he has clearly shown he can have stretches of dominant play. I would be buying Severino now while his value is relatively low. A minor adjustment is all he needs to return to form.

Verdict: Buy

Drew Pomeranz, Boston Red Sox

Season K-Rate: 26%, Last 30 K-Rate: 22%

When the Red Sox acquired Drew Pomeranz, he held a 2.47 ERA and 1.06 WHIP over 17 starts with the Padres. He hasn’t carried that same success with him over to the Sox. Though 20 total starts, he holds a 4.82 ERA and 1.39 WHIP. His strikeout rate is up from last season, but over his past few starts the strikeouts have gone down. He left his last start with triceps tightness, but luckily did not have to miss a start. He was able to last four innings on Saturday while striking out six. It took him 97 pitches to get through those innings.

Pomeranz has had a tough time keeping the ball in the yard in his time with the Sox, with a 19.7% HR/FB last season and an 18.9% HR/FB this season. His soft contact % is up this season, but his hard hit % is still at 35.1%. He had similar results to this while he was pitching for the Rockies, though his strikeout rate is much improved since then. It wasn’t until he went to an excellent pitchers environments in Oakland and San Diego before he succeeded. He is using the same mix of pitches and velocities as years past, but since he’s gotten to Boston the positive results have been inconsistent at best. His current FIP/xFIP of 4.65/3.81 show some positive regression are coming his way, though with the difficulty of his division and the ballpark he’s in he may not see the results fantasy owners were looking for when they drafted him.

Pomeranz has struggled mightily in his time with the Red Sox, and while the strikeout numbers may be there it’s hard to stomach that ERA. Now isn’t the time to sell with how poorly he’s pitching and his minor injury, but keep expectations in check for the lefty moving forward.

Verdict: Hold/Sell

More Risers and Fallers

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