Strikeout Rate Risers and Fallers for Week 14: Buy or Sell?

Due to a combination of harder throwers and hitters focusing on hitting for power, strikeouts are at an all-time high in baseball. For pitchers, this is an ideal trend. The ability to generate swings and misses is the most important skill to possess, as it's the only true way to control what happens after the pitch is thrown and eliminate the randomness that the ballpark, fielders, weather, and luck can play.

The stat is equally important for fantasy players. Not only are strikeouts a category in every league, but K-rates are often indicative of overall production. A pitcher with a 4.50 ERA with a 25.0 K% may see some positive regression in the future. On the other hand, a hurler with a 3.00 ERA and 16.0 K% may not see the ball continue to bounce their way.

In this column, we'll review two strikeout rate risers and fallers to determine if their performance will improve, hold steady, or worsen as the season moves along.

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Risers

Derek Holland, San Francisco Giants

2018 K-Rate: 22.1%; Last 30 Days: 28.2%

Long gone are the days when Derek Holland was one of the promising young arms in baseball. After pitching a career-high 213 innings and registering a personal best 4.3 fWAR in 2013, he pitched in only 16 games in the next two years due to injuries. When he returned, he wasn't the same pitcher any longer. In 2016 and '17, he posted a combined 5.65 ERA and his value was equal to a replacement-level player in 242 1/3 innings. With his career on potential life support, he signed a minor-league deal with the Giants this past offseason and made the rotation after injuries to Madison Bumgarner and Jeff Samardzija. Through May, he looked like the pitcher of the last two years, posting a 4.94 ERA in 11 starts. Since the calendar has flipped to June, however, he's looked like the vintage Holland who disappeared five years ago.

Holland put up a 2.70 ERA for the month, and the peripherals supported the strong performance (3.25 FIP, 3.32 xFIP). His strikeout rate rose (obviously, since you're reading this column) to borderline elite levels, while his walks fell to 8.2%. Was June a fluke for the southpaw, or has he finally regained his previous form at age 31? A strikeout rate approaching 30% is certainly a reason to turn heads, and an equally impressive 13.1 SwStr% is enough to give Holland more than a passing glance.

One potential explanation for the recent improvement is a move to the opposite side of the pitching rubber, switching from the right to the left. But he didn't even begin doing that until two starts ago. So what changed before that? Both of his breaking balls — a slider and a curveball — have been wicked during this streak, at least in terms of whiffs. Per Brooks Baseball, both pitches registered a 22% whiff rate in the month of June. However, Holland flip-flopped his preferred breaking pitch, using the slider (21.8%) more often than the curve (15.7%), which deviated from his pitch choices the first two months of the season (22.7% curve, 11.0% slider).

The most noteworthy aspect of that change is Holland is seemingly returning back to his former pitch selection. In 2013, he used his slider 24.0% of the time and seldom spun a curve (4.9%). It made sense, as the slider has always been his best swing-and-miss offering. That year, it registered an elite 24.5 SwStr% compared to a poor 8.6 SwStr% for the curve. The last two seasons, which followed bouts with knee and left shoulder injuries, he shied away from the slider (11.4%) in favor of the curveball (20.4%), and the results were ugly.

The whiff numbers, pitch selection, and heat map (left: April/May; right: June) seem to indicate he gained a better feel for his slider in the month of June.

Whether this trend continues remains to be seen. Improved control and command helped Holland toward a resurgent June, but it's not a large enough sample size to say he's once again a viable fantasy pitcher. For those in deeper leagues, however, he's someone to monitor if you need help at the position.

Chase Anderson, Milwaukee Brewers

2018 K-Rate: 19.1%; Last 30 Days: 23.6%

Although he had a breakout 2017, Chase Anderson was one of the most popular regression candidates among pitchers heading into the 2018 season. While his overall results aren't horrible on the surface (4.18 ERA), he hasn't replicated his out-of-nowhere success from 2017 at age 29. The peripherals tell an even scarier story (5.45 FIP, 4.89 xFIP) due to a rising walk rate (9.8%) and a declining strikeout rate. Anderson turned in a solid June, however, with a 3.78 ERA and his K% rising from 16.6% to 23.6%. While control problems have persisted (10.2 BB%), the right-hander has seemingly turned a corner and returned to his 2017 form. In addition to the strikeout increase, his 17.6% homer-to-flyball ratio through 10 starts, which resulted in a whopping 13 home runs allowed — one shy of his total for the entirety of 2017 — normalized to 12.9%. A deeper dive into the numbers paints some concerns, though.

Despite boasting a slightly above-average strikeout rate last month, Anderson still had trouble missing bats, indicating the strikeout increase may not last. His SwStr% in June (8.5%) actually dropped from the first two months of the season (8.7%) and continues to sit well below the league average (10.6%) overall. Only one of his pitches, the changeup, has better than a 10.0 SwStr% on the season, and even that pitch has dropped from its 2017 mark. Even over the last 30 days, only his four-seam fastball had better than a pedestrian whiff percentage (13.3%).

The hope primarily comes from his last two starts against the Cardinals and Reds, when he had a 12.0 and 13.2 SwStr%, respectively. His start against Cincinnati was particularly encouraging, as he got swings on a season-high 46.2% of pitches he threw outside the strike zone — far superior to his previous best of 33.9% set back on May 6. Against a Reds team that ranks in the top 10 in both categories, that's an impressive feat. Anderson's changeup has shown signs of coming back to life in his last two outings (19.2% whiff rate), and his four-seamer continues to be a solid swing-and-miss offering (17.8% whiff rate) as he embraces throwing it up in the zone. Here's a look at his fastball location in the month of June (left) compared to the first two months of the year (right):

Anderson clearly has a plan to keep his fastball up in the zone, and if can continue to command it while keeping the changeup down, it may be the key to success. Still, a sample size larger than two games is needed before fantasy owners can get too excited over the recent strikeout surge.

Fallers

Eduardo Rodriguez, Boston Red Sox

2018 K-Rate: 24.8%; Last 30 Days: 17.7%

Finally healthy after battling knee injuries for a large portion of last season, Eduardo Rodriguez was a breakout hopeful heading into 2018. Although he hit some speed bumps in April, the southpaw found his stride in May. He finished the month with a 3.18 ERA and an elite 30.7 K% — not bad for a guy who was supposed to be the fourth starter on his team. Just as it seemed he was ready to break through, Rodriguez came upon hard times in June. While his first three starts were solid, the strikeouts were down aside from a nine-punchout game against the Mariners on the 17th. In his last two starts, he has only four strikeouts in 10 innings, made even worse by allowing nine earned runs in those two outings. The pair of performances ruined his six-start winning streak, but should they give fantasy owners any pause moving forward?

In his last two starts, Rodriguez managed a 5.8 and 4.2 SwStr%, by far his two lowest outputs in any appearance this season and worst in any outing since 2016. As a pitcher who thrives on keeping hitters off balance with a fastball-changeup combo, that's the first place to look for answers. For the month, Rodriguez still got plenty off whiffs with his change as usual (24.2% whiff rate). That number drops to 18.8% and 11.1% in the last two starts. One reason for that, as manager Alex Cora wondered after Rodriguez's latest start, might be that he isn't getting enough separation in velocity between his fastball and changeup.

In April and May, the difference between the two pitches was 6 mph. That dipped to 5.1 mph in June. It doesn't seem like a huge jump on paper, but a full mile per hour can make a big difference to hitters. With that said, in his outing with his lowest difference in fastball and changeup velocity (4.26) on April 26, he still got plenty of whiffs with his changeup (32.4% whiff rate) and allowed only two runs. So while that likely does have an impact, it's not the whole story. What else could be at play? He's still getting hitters to whiff at his changeup, he's still getting them to chase outside the strike zone (32.5 O-Swing% in April/May, 33.4% in June) at an above-average level, and he's walking fewer hitters (7.8% in April/May vs. 6.5% in June). Why is he suddenly struggling to miss bats?

The most logical answer lies in his fastball command. The four-seamer held batters to a .322 slugging percentage in April and May. His secondary fastballs, the sinker and cutter, also had limited damage against them (.400 SLG vs. the sinker, .237 vs. the cutter). Here are the slugging percentages against the four-seam, sinker, and cutter, respectively, in June: .605, .444, .464. The spike is most likely caused by poor fastball command within the strike zone, and it's hurting his ability to miss bats. Since the four-seamer is his primary pitch, we'll focus on that. Take a look at the difference in heat maps between April/May (left) and June (right):

In the first two months of the season, Rodriguez seemed to have a plan for how to use his fastball and executed it well; notice the consistent location in the strike zone. In June, the fastball got erratic up in the zone. Both months, though, show a lot of pitches being left up in the zone. In the first two months of the season, luck was on Rodriguez's side. Despite allowing a 91.5 mph average exit velocity on his fastball, he held hitters to a .250 batting average on balls in play. The exit velocity dropped to 88.2 mph on the pitch in June, but the BABIP luck was not in his favor (.448).

Painting the corners moving forward — or elevating his fastball a bit more — will be important for Rodriguez. Of note, he began to use his four-seam fastball less in June and favored his sinker more, perhaps in an effort to keep the ball down with more regularity, though the results haven't come yet. Time will tell whether he sorts through this rough patch, but for now, Rodriguez should stay rostered in every fantasy league because his changeup makes him a strikeout threat every time he toes the rubber.

All stats as of Sunday, July 1.

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