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.

K-Rate Risers

Jacob deGrom, New York Mets

2016 K-Rate: 23.7%, 2017 K-Rate: 31.6%

You could tell back in 2014 when Jacob deGrom made his debut for the Mets that he was going to be something special. He owns a career 2.81 ERA and 1.11 WHIP, with a 2.90/3.12 FIP/xFIP to back those numbers up. His career K% is 26.1%, but last season it got down to 23.7% likely due to some lingering injuries he sustained. This season he is healthy, and has ratcheted things up a bit with a K% of 31.6% through six starts.

This season deGrom sports a 3.68 ERA and 1.36 WHIP, which can be attributed to a bit of bad luck. His BABIP is inflated at .349, and his HR/FB is nearly 4% higher than his career average at 13.3%. His FIP/xFIP of 3.10/3.04 also point to better things ahead. His swinging strike rate (SwStr%) is at a career high 15.6% this season, and for the first time in his career every single one of his pitches has a double-digit SwStr%. His fastball velocity is back up to 95 MPH on average this season, which helps set up his devastating off-speed stuff. He does carry an uncharacteristic 10.3% BB%, which is the only chink in his armor. Still, his strikeouts are up and he’s allowing less contact than last season, so I like his odds to continue dominating and striking out hitters at a high clip.

Only once before this season did deGrom allow five free passes in a game. It was the third game of his career back in 2014. This season he has done it twice, though it seems more like him shaking off the rust than any lingering effects. I would buy deGrom while his ERA is slightly inflated.

Verdict: Buy

Trevor Cahill, San Diego Padres

2016 K-Rate:23.2%, 2017 K-Rate: 29.8%

Trevor Cahill was last a full-time starter in 2013 with the Diamondbacks, when he held a 3.99 ERA and 1.42 WHIP over 25 starts. In 2014, he was moved between the rotation and bullpen, before sticking as a reliever for two seasons. He was signed by San Diego to start, in what was expected to be a poor rotation. Surprisingly the rotation as a whole hasn’t been bad, and Cahill has impressed. Through five starts he holds a 3.60 ERA and 1.17 WHIP, supported by a FIP/xFIP of 2.64/2.82. Not to mention his career-high 29.8% K%.

Looking into the numbers, it doesn’t seem like Cahill is doing much different than in the past. His pitch velocity is the same, he has the same repertoire, and he is still generating a lot of ground balls. One thing he has changed is his curveball usage. For his career he has thrown the hook about 11% of the time, but in 2017 that is up to 27%. The pitch has held hitters to a 0.57 batting average against, with a 23.4% SwStr%. It has kept hitters extremely off-balance, which shows in his numbers. Cahill has an outside swing rate (O-Swing%) of 37.5%, and a zone swing rate (Z-Swing%) of 49.5%. Both are trending in the right direction from his career averages of 27.1% and 57.5% respectively. Basically, hitters are swinging at pitches outside of the zone more often and pitches inside the zone less often, which has helped drive his strikeout numbers up.

Cahill’s curveball is a fantastic pitch; however he is still allowing a 40% hard hit rate which will likely catch up with him. He certainly won’t punch out 11.10 hitters per nine all season, but nothing in his profile suggests he is simply getting lucky with these early results. Don’t expect greatness with Cahill, however, a season like he had in 2012 isn’t out of the question. That season he threw 200 innings with a 3.78 ERA, which is certainly useful in fantasy.

Verdict: Buy

K-Rate Fallers

Vince Velasquez, Philadelphia Phillies

2016 K-Rate: 27.6%, 2017 K-Rate: 22.6%

Vince Velasquez certainly has ace-level stuff; we’ve seen it in flashes. In his second start of 2016, after being acquired by the Astros, he threw a complete-game shutout with 16 strikeouts against the Padres. In the first month of the season he held a 1.78 ERA with 33 K’s in 25.1 innings. Then in May, he held a 2.12 ERA with 34 K’s in 31.2 innings. Inconsistency has been Velasquez’s Achilles heel. He ended the year with a 4.12 ERA, 1.33 WHIP, and a K% of 27.6%.

Through five starts this season he holds a 5.47 ERA, 1.44 WHIP, and a K% of 22.6%. Hitters aren’t hitting as well for average off him this season, but he is striking out less hitters and his BB% has risen from 8.2% last season to 13%. He began the season with 17 strikeouts in his first two starts, but has only nine over his last three starts. He is throwing his changeup more, which wasn’t successful last season and hasn’t done him many favors this season. Hitters have hit .333 off the pitch this season, and his .373 off it last season. His pitch velocities and SwStr% all look similar to last season, however his O-Swing % and Z-Swing% are trending in the wrong direction. Hitters are more patient on the plate, and waiting for him to throw in the zone before they swing which has led to the increased walks.

The book is out on Velasquez and hitters have adjusted, now it is time for him to adjust. When he is on he can strike out any hitters, unfortunately when he’s off he can be extremely hittable. It would be tough to sell him now, but if I could get a solid piece from another team I would rather they deal with these continual bumps in the road.

Verdict: Sell

Chris Archer, Tampa Bay Rays

2016 K-Rate: 27.4%, 2017 K-Rate: 22.4%

Chris Archer has been a workhorse for the Rays over the past three seasons. He has not started less than 32 games per season over that span, with a 3.52 ERA and a 9.74 K/9. In the past two seasons he has finished in the top-6 in the league in strikeouts, with a K/9 just over 10.00 each season. This season things have been different. While he does have a tidy 3.43 ERA over his first six starts, his strikeout rate has dipped. His career K% is 24.8%, though the past two seasons it has been 29% and 27.4%. This season it is back down to 22.4%.

While his pitch velocities all remain similar this season, his pitch selection has not. Archer has primarily thrown his fastball over his slider and changeup, but this season he has thrown more sliders than fastballs (302 to 300, according to Fangraphs). The O-Swing% on the slider is at 38.6%, its lowest rate since 2012. Archer’s O-Swing% is down across the board, though all of his other swing and contact stats are in line with his career averages. His SwStr% of 11.8% isn’t as high as it was the past two seasons, but it is higher than any other year of his career.

With everything else looking normal, it seems as if this small patch of decreased strikeouts is nothing more than just that. Archer has been a K-machine for two seasons, so expect him to make a bounce-back in that area over his next several starts. If you know an owner who is worried about his strikeout production, it would be wise to snatch him up.

Verdict: Buy

More Risers and Fallers

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