Second-Half Breakouts: Examining June's K-BB% Leaders

July 3, 2021

Eric Samulski examines the K-BB% leaderboard for starting pitchers in June, 2021 to identify potential SP risers and breakouts for fantasy baseball.

In my last article, I mentioned that K-BB% is one of my favorite stats for looking at a pitcher's in-season performance. There are two main reasons for that. First, it stabilizes quickly and has a proven correlation to a pitcher's overall success. Second, it's impossibly simple. If a pitcher has a high strikeout rate (K%), then we know he is effective because we know that strikeouts and good and a sign of deception and good stuff. However, if a pitcher also has a high walk rate (BB%), then we know that the pitcher can't harness that stuff and gives up a lot of baserunners. K-BB% thus allows us to identify pitchers who can not only miss bats but also have the command to make use of their strong pitches.

Taking that simple premise, I decided to look at the K-BB% leaders for just the month of June. While it's not an exact science, the idea is to hopefully identify some pitchers who are hitting their stride in the summer and might have better rest of season value than we had anticipated.

I pasted the whole list of the top-25 pitchers so that you could have that information for yourself and then wrote up some quick blurbs for some pitchers I thought were worth a little extra attention.

The List

Pablo Lopez, Miami Marlins

Pablo Lopez doesn't get enough respect. That's it. That's the blurb. (Ed. note: Don Mattingly approves this message)

Robbie Ray, Toronto Blue Jays

People are still waiting for the other shoe to drop here. It's not happening. Ray's increased fastball velocity has sustained, as he averaged 95.3 mph on the four-seam in June, which is right in line with his season numbers. He continued to pound the zone with the fastball, throwing it 56.2% of the time in June with a 63.5% zone rate. The pitch has a strong 12.6% swinging-strike rate (SwStr%) and 31% CSW, but the beauty of pounding the zone with the fastball is how it sets up his slider and curve so well.

Yes, the fastball will get hit and Ray will give up home runs. He has a 22.1% HR/FB ratio this year, and I wouldn't expect it to change that much. However, that doesn't mean he can't remain an effective pitcher now that his BB% has plummeted from 17.9% last year and 10.6% on his career to just 6.2% this year. Throwing more strikes makes his stuff play up more. Who knew?

Eduardo Rodriguez, Boston Red Sox

We've talked about Rodriguez a bunch of far this year since he is drastically underperforming his peripherals and predictive stats. He currently has a 5.83 ERA but a 3.38 xFIP and 3.48 SIERA. The K-BB% growth is also because Rodriguez is walking a career-low 2.17 hitters per game, which is a 5.6% walk rate. Early on in the year, it was understandable to question that, but we've now seen it for three months. The biggest issue for Rodriguez has been his changeup, which, along with his cutter, has been one of his best pitches over the years.

The cutter induces soft contact and the changeup gets whiffs, only the changeup has a 15% SwStr this year and 27.2% whiff rate, compared to a 37% whiff rate in 2019. The cutter has been giving up contact at a higher launch angle than years past and has so far resulted in a .333 batting average against and .508 slugging against. Here we run up against the same issue. The x-stats say the pitch deserves a .229 average and .353 slugging percentage. That's a massive difference!

In the end, we can't just expect Rodriguez to eventually hit his x-stats. We know that. However, we can use them to reveal that this is a pitcher who is getting truly unlucky - as his .374 BABIP and 62.4% left on-base rate will attest. Over the course of the season, those luck metrics will normalize. Then you have a pitcher who has maybe traded some swing-and-miss for better control, which maybe makes him similar to the pitcher he has always been. Since that's a 3.81 ERA arm now with better ratios, that's not such a bad player to roster.

Patrick Sandoval, Los Angeles Angels

Sandoval is another popular name of late, riding his plus-plus changeup back to fantasy relevance. After beginning the season out of the rotation, Sandoval has forced his way back into consideration with a 3.89 ERA, 3.78 xFIP, and 3.93 SIERA. His profile on the whole has generated an impressive amount of swing-and-miss with a 16.4% SwStr% and a 33.9% O-Swing%, which has helped contribute to a 31.7% CSW. However, the star is the changeup. Despite being in the zone only 33.2% of the time, it has a 32.8% SwStr% and a 37.1% CSW. That's tremendously valuable since his most used pitch at 32% but is also his second-most used pitch with two strikes.

Yet, what has me optimistic about Sandoval is another change he's made in June: he started to throw his slider more, going from around 7% usage early in the season to as high as 25.3% in his last outing. That's an important development since it's actually been his second-best pitch this year, registering a 25.5% SwStr% and 40.8% CSW. Sandoval had been using it mainly as a two-strike offering but has begun using it more early in the count, which is a good thing since many studies have conclusively shown that sliders are the most effective pitch in baseball and don't need to be limited to just being used to same-handed hitters.

As Sandoval gets more confident in using the slider across various counts, I'd love to see him dial back on one of the four-seam or sinker, since they are both below-average pitches and he really doesn't need to keep using both of them. Regardless, I'm investing in a strong second half from the Irish Panda (trademark Nick Pollock).

Andrew Heaney, Los Angeles Angels

Don't do this to yourself. Just don't. The 22% K-BB% comes with a 5.67 ERA and a 1.44 WHIP. Yes, the SIERA and xFIP are both in the mid-threes, suggesting he's pitched better than his results, but we've done this enough times, haven't we? Are you ever going to feel comfortable starting Heaney? Why do this to yourself?

Adam Wainwright, St. Louis Cardinals

Wainwright is continuously disrespected due to his age. The 39-year-old has been tremendous for much of the season with a 3.49 ERA, 3.70 xFIP, and 3.89 SIERA. On the season, Wainwright has seen a slight decrease in O-Swing%, and SwStr% from last year and is benefiting from some additional called strikes, which could be worrisome on the surface.

However, his strong June also coincided with him using his curveball and cutter more and his sinker a little less. It wasn't a drastic change, but could easily have explained the boost in strikeout rate since the curve has a 13.1% SwStr and the cutter has a 12.1% SwStr, both of which are the only two pitches he has with SwStr% over 5.3%.

The sinker has been a good pitch for inducing weak contact with a .167 batting average and 1.87 deserved ERA (dERA), so it's a foundational pitch for him. However, I love the increased reliance on curve and cutter and hope it stays. Regardless, Wainwright is often treated as a boring veteran arm, but I think he can act as a reliable and beneficial pitcher for your fantasy team over the final three months.

Joe Ross, Washington Nationals

I'm not gonna lie, I thought the Joe Ross fantasy experience would have been over by now. I loved that the 28-year-old was throwing his slider more to start the year, but I just didn't think the arsenal was good enough to hold up over the long-term. Yet here we are in July and he has a 4.02 ERA, 4.29 xFIP, and 4.20 SIERA on the season. Those are all solid numbers, however his June was even better with a 1.95 ERA and that 21.1 K-BB% over 32.1 innings.

What's confusing is that I don't see any major change in his pitch mix. He threw the fastball a little less and the sinker a little more, but we're talking like 2%. The four-seam was a 0.6 MPH harder, which may be from the warmer weather, but it doesn't explain how the fastball went from a .500 average against and 1.100 slugging allowed in May to a .143 average and .357 slugging in June.

If you look at the schedule, he didn't face weak competition. He had a bad start against the Mets, but also shut out the Giants over eight innings (striking out 9), gave up three hits over six scoreless against the Phillies, and struck out seven while allowing two runs over 6.1 innings to the Rays. I'm just confused and I can't really see this lasting. Ross has one really strong pitch with a slider that has a 16.1% SwStr% and 30.4% CSW. His sinker gets a lot of called strikes, which enables it to register a 34% CSW and 4.08 dERA, but the fastball has a 7.86 dERA and this is not really a strong month that I think will continue to carry over.

Dylan Cease, Chicago White Sox

I wanted to highlight Cease because his June was actually not really good on the whole. He was still able to rack up strikeouts, but he had a 5.04 ERA and allowed a .252 average against. The biggest difference was in his fastball. The four-seam went from a .200 average against and 36.7% whiff rate in May to a .297 average against and 14.3% whiff rate in June. That's a loss of over 22% on the whiff rate!

A big reason for that may be connected to Cease losing over 200 rpm on average on the pitch. Losing that much spin means less rise, which means the fastball is more hittable. This could easily be tied to the cutback on "sticky stuff," but it is absolutely something we need to monitor. Hopefully, Cease can make adjustments to gain back effectiveness on the fastball, but if he's not able to, that early-season breakout we witnessed may not last through the summer.

What If We Cheated?

For you-know-what and giggles, I'd lowered the minimum number of required innings to 10, and three names entered the list that I just want to put on your radar: Chris Paddack ranked seventh (27.9% K-BB% and a 2.08 xFIP), Zach Thompson ranked 10th (26% K-BB%), and Logan Gilbert was 16th (23.7% K-BB%).

Paddack is still not where we want him to be, but the increased swing-and-miss is a clear positive step, and the poor ERA is really inflated from one bad start against Arizona. I think we're close to seeing him put it together for a dominant outing and maybe a strong second-half run.

I covered Thompson in my last article, so check that out for a deeper dive, This is also further evidence that Logan Gilbert is settling in from his up-and-down first few starts. He has a 2.79 ERA in June and just a 0.93 WHIP and .186 average against. Expect some bumps because he is still a rookie arm, but I think Gilbert could be in for a strong second half and I would be looking to add him in redraft if he has one bad start that leaves a manager questioning his value for this year.

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