Analyzing K-BB% gainers from 2020

Evaluating pitchers isn’t historically my thing, but I’m working on it. Welcome to the journey! At the very least, after today I expect to have a better sense of what sort of pitcher each of these guys is. That, to me, is more valuable than any set of rankings.

Today I am examining K-BB% gainers from this past season. It’s a bit simplistic, but I know generating strikeouts and limiting walks are both good things. But sometimes bad luck can make things go sideways, as is the case for at least one of our pitchers today. And some names on this list will be obvious. And some may not be interesting due to having low walk rates (and mediocre strikeout rates). Ultimately, my hope is to unearth a specific change that makes me feel confident about a guy’s prospects moving forward–be it a change in pitch mix, some added velocity, or another factor entirely.

So let’s see who stands out atop the leaderboard of K%-BB% gainers from 2019 to 2020. And as always, I’m open to crowdsourcing some research. If you know something about one of these guys that gives you a strong opinion in either direction, by all means share it in the comments so we can all improve at the fantasy baseball game. Here are the top 10 K-BB% gainers from 2019 to 2020 (min. 150 IP):

RankPlayer Name2019 K-BB%2020 K-BB%Total Gain
1Trevor Bauer18.8%29.9%11.1%
2Zach Eflin11.5%22.4%11.0%
3Marco Gonzales10.5%20.6%10.1%
4Kenta Maeda18.9%28.2%9.3%
5Shane Bieber25.5%34.0%8.5%
6Zach Davies7.6%15.9%8.4%
7Aaron Nola17.5%25.3%7.8%
8Jose Quintana14.2%22.0%7.7%
9Joe Musgrove16.4%23.5%7.1%
10John Means13.0%19.9%6.9%

If Quintana seems odd to you, you’re not alone. He only tossed 10 innings in 2020, and he allowed a whopping 94.5 MPH average exit velocity. I think we can let that pitch go by, as Quintana is a 32-year-old free agent who throws 91 MPH. He also hasn’t had an ERA under 4.00 since 2016.

That, and you shouldn’t need to be told to draft Trevor Bauer, Shane Bieber, Aaron Nola, or Kenta Maeda. All have ADPs inside the top 50 this draft season, and three of the four are top 25 picks.

That leaves us with Eflin, Gonzales, Davies, Musgrove, and Means…which is a really super group to dive into.

Lastly, and for reference…the league average K-BB% in 2019 and 2020 for all starters was 14.6%. So our sample of five hurlers were all well above average in 2020. So if we really believe any of these guys can repeat their 2020 performances, then we could have some solid plays for 2021.

Zach Eflin severely increased his sinker usage in 2020.

NFBC ADP: 201.52 (min 164, max 254)

Eflin’s ADP has been fairly consistent this draft season, essentially moving from 220 to 200 from October to December. So despite a little helium from the fantasy community, if you liked his initial ADP you are probably still “in” on him.

Eflin’s fastball velocity was steady from 2019 to 2020, 93.6 MPH in ’19 and 93.9 MPH in ’20. The most discernible change was his pitch mix, as he threw FAR more sinkers in 2020. He used the pitch a whopping 52% of the time, up from only 22.3% in 2019. The tradeoff was essentially ditching his four-seamer, from 33.3% usage in 2019 to only 9.1% in 2020. This SHOULD help Eflin avoid implosions, as he’ll be more of a worm-killer with grounders and not give up as many fly balls. That was the case on a macro level in 2020, as Eflin posted a career-best 47.4% ground ball rate and an above-average 1.22 HR/9–the second-best HR/9 of his career.

What I’m struggling with is the throwing of the sinker–a pitch designed for contact–and Eflin having so many more strikeouts in 2020 (career-high 28.6% K-rate). His 36.8% chase rate was pretty stellar, but hitters still made contact out of the zone at an above average 65.0% rate. Also, his overall contact rate was 78.9% (worse than the 75.3% league-average). And sure, perhaps a lot of that contact isn’t scary if it’s on the ground. But Eflin’s swinging strike rate was over 7.2% on a pitch that he threw over half the time. His overall swinging strike rate is still below average, at only 10.2%. Two things can be true at the same time, I suppose. First, perhaps Eflin can keep it going and is becoming a more effective MLB pitcher. But secondly, that doesn’t mean he’ll be a sudden ace in fantasy baseball. And that is where I lean for 2021 given that I think he will have an average strikeout rate, or slightly above average, at best. The curve offers some hope for whiffs, as it had a .103 BAA and a 45.0% K%. But I still can’t see Eflin getting close to 2020’s strikeout rate. I think he’s a solid back-end rotation piece, but not someone who offers tons of upside.

NFBC ADP: 175.19 (min 141, max 216)

By month, his ADP is 140 (Oct), 156 (Nov), and 175 (Dec). So if you were in early, you should still be in now. Me, I’m unsure. Gonzales did beef up his K-rate to a respectable 23.1% in 2020, essentially right at the MLB average. And he didn’t walk a soul, checking in with a measly 2.5% walk rate–he tied Kyle Hendricks with the best mark among all qualified starters. The phrase control artist applies. Gonzales’ career walk rate is only 5.9%, so the control has always been a feature. But under 3% isn’t something I’d want to bet on again. He could regress in this area and still be really good.

Gonzales’ improved strikeout rate didn’t come by way of a better swinging strike rate, as his 8.4% mark was entirely pedestrian (below average, even). He still pitches to contact, and he even allowed a smidge more zone contact in 2020. His 34.1% chase rate was solid, but also in line with his previous two years (33.4% and 35.9%). His average fastball velo was 88.2 MPH, which was in line with 2019’s 88.9 MPH average. It was also the lowest average fastball velo of his career. Sooooo, nothing to report so far as being dramatically different.

His pitch mix changes were a little subtle–he increased the use of his four-seamer by 6% and his cutter by 4%. But the most discernible switch was ditching his changeup, from 24.1% in 2019 to only 14.4% in 2020. Looking deeper, this doesn’t appear to be a decision made based on 2019 results. That year, the changeup had a .244 BAA, which was the best the pitch had ever performed for Gonzales. Same is true for the .288 wOBA–that was also the best the change had ever performed. But in 2020 the change got pasted, with a .302 BAA, .383 wOBA, and .256 ISO against it. I’d have stopped throwing it, too.

Luckily, the four-seamer was better than ever, with a .114 BAA, .068 ISO, and .150 wOBA against. The cutter also fared well. But I’m not really finding much to support the growth in strikeout rate. What Gonzales does is command four pitches well and change speeds, and induce a lot of weak contact. I suppose his comp is Kyle Hendricks, at least for what he offers us in fantasy baseball. Here are last year’s performances by those two:

Kyle Hendricks62.881.0064
Marco Gonzales73.100.9564

And here are the Steamer projections for 2021:

Kyle Hendricks114.341.28153
Marco Gonzales104.421.30142

The league-average WHIP among qualified starters in 2020 was 1.30, and the average ERA was 4.46. Gonzales’ career marks are a 4.09 ERA and a 1.29 WHIP. So at the very least, he should aid in stabilizing ratios for your fake team. And at his best–if he holds onto some of his 2020 gains–he’ll really help you in WHIP. At ADP, I’d prefer Gonzales (175) over Hendricks (87). Hendricks’ safety is being drafted as soon as Round 5 in some places (he went at pick 67 in my current DC). That’s just too rich a territory for me. And honestly, I’m not even enthused about Gonzales. He’s more of a guy I’d select if I took some risks early AND if he fell closer to his max pick. Maybe I’m just a sucker for strikeouts…let me know in the comments.

NFBC ADP: 233.90 (min 185, max 275)

Davies was traded to the Cubs in the deal that sent Yu Darvish to the Padres. Like Gonzales, limiting walks has always been a strength. He has a career 6.9% walk rate, but in 2020 the big switch was growth in his strikeout rate. He has a career 17.3% K-rate and was at 17.5% (2018) and 15.2% (2019) in recent years. However, in 2020 his 22.8% mark was by far the best of his career (if still a hair below the MLB average). His fastball velocity was remarkably steady, from 88.5 MPH on average in ’19 to 88.6 MPH on average in 2020.

This looks like a pitch mix switch, as Davies traded out sinkers for more cutters and changeups. The result was tying his career-high 10.0% swinging strike rate (still below average) and tying his career-best 75.8% contact rate (right at average). The same is true for zone contact rate, it was also right at league average. And Davies doesn’t make batters chase–he’s been just below 30% in each of the last two seasons. I think Gonzales’ superior chase rate and better walk rate make him the better play to keep things going in 2021, but there’s a large discrepancy in ADP among these guys that also needs to be considered. For what it’s worth, Steamer doesn’t like Davies much at all, giving him a 4.93 ERA and 1.45 WHIP as a projection. I think that’s a little light for a guy who has posted a 3.30 ERA and 1.22 WHIP over the last two seasons (229 innings). I view Davies as a guy I can tolerate if I think I need ratio help at the back end of my rotation. If I need strikeouts I’d look to a guy like Nathan Eovaldi instead, who is being drafted in the same range. Just depends on what you need.

Joe Musgrove had a career-high 33.1% K-rate in 2020. (Photo Credit: Charles LeClaire-USA TODAY Sports)

NFBC ADP: 127.52 (min 110, max 158)

Musgrove is a buzzy name, as you can tell by the ADP. He managed a career-best 3.83 ERA in 2020 (39.2 innings). It was backed by a 3.42 FIP and 3.23 xERA. He generated more ground balls than ever, and induced a ton of weak contact. He ranked inside the 93rd percentile (top 7%) for average exit velocity, at only 85.1 MPH on average. If that wasn’t enough, his 33.1% strikeout rate was inside the top 10% of the league. His Statcast profile is littered with deep red, save for his fastball velo (33rd percentile) and his walk rate (39th). The walks I can live with (9.6% rate in 2020) if the strikeouts hold, though. There’s also the fact that Musgrove has always been a control guy. He has a career 5.8% walk rate in the majors, and control was a feature in the minors as well. If I had to bet on it, I’d say his walk rate is below 9.6% in 2021.

So, will the strikeouts hold? That’s the bigger question. Musgrove’s contact rate was elite in 2020, at only 68.9%. That would have ranked fifth-best in the league had he qualified, trailing only deGrom, Bieber, Giolito, and Maeda. His 14.4% swinging strike rate was also elite–it would have tied for ninth-best with Yu Darvish. For reference, here are the eight names who were better: deGrom, Giolito, Maeda, Bieber, Castillo, Cole, Carrasco, and Scherzer. You’ve maybe heard of those guys? So with regard to not allowing contact and pure swing-and-miss, Musgrove was in elite company in 2020.

Musgrove’s velocity was steady, at 92.5 MPH in 2020 after averaging 92.4 MPH in 2019. So what was different? His sinker, changeup, and slider usage were all pretty steady, but he traded out fastballs (37.9% to 27.0%) for more curveballs (9.2% to 19.9%). Musgrove’s four-seamer was rocked in 2019, to the tune of a .243 ISO and a measly 10.3% whiff rate. In 2020, it went from bad to worse–a .351 ISO and 14.0% whiff rate. The curve, though? The curve was epic in 2019, with a .180 BAA and a 43.1% strikeout rate–the only blemish being the .213 ISO. In 2020, it all came together. The curve had a .050 BAA, .000 ISO, 59.1% strikeout rate, and mere 4.5% walk rate. Musgrove induced ground balls at a 71.4% rate with his curve, and not one single solitary fly ball (0.0%). Pretty easy to keep the ball in the yard if no one is hitting it in the air, huh? You’re paying an expectant price for him, but I like the upside given the depth of his arsenal. And while he doesn’t have the best fastball velo, but he is elite with regard to spin rate. Here’s a little more Musgrove propaganda from our own Jorge Montanez:

I am in on Musgrove in 2020 given the steep cliff that is reliable starting pitching. Give me all of Musgrove’s upside when starting pitching starts to get murky.

NFBC ADP: 216.86 (min 183, max 248)

Here’s a gem from Alex Fast of Pitcher List:

That’s a nice way to start off, as it makes Means’ ghastly 2.34 HR/9 in 2020 far more tolerable to look upon. In his breakout 2019, Means posted a 1.34 HR/9, and the MLB average for all starters last year was a 1.40 HR/9. So if he can at least revert to 2019 levels, he’ll be fine. His 82.8% LOB% in 2020 was also 10% above the MLB average, and well above Means’ own 75.9% mark in 2019. So he could also experience some positive regression in that area.

On the plus side, Means’ average fastball velo increased to 93.8 MPH in 2020, solidly above 2019’s 91.8 MPH average. He also basically added a fourth pitch, with his curve usage spiking from 6.0% to 12.6%. Means allowed less contact overall and less contact in the zone in 2020, and his swinging strike rate leapt from 9.9% to 12.5%. He now has a 5.4% walk rate allowed over his 202 career innings, and he posted a minuscule 4.0% mark in 2020. For so long as his contact rate inside the zone remains above-average, I see no reason why he shouldn’t keep attacking hitters in the zone and continue limiting his walks. There’s a lot of upside here for a guy who can round out your fantasy rotation.

SUMMARY (draft strategy)

Of the five, I’m most likely to pay up for Musgrove or wait on Means (or both!). Then I suppose it would be Eflin, Gonzales, and Davies (in that order). Typically I’m avoiding the control types like Gonzales and Davies. Again, I’m probably just too in love with the holy strikeout–maybe I’m guilty of chasing those at the expense of my ratios sometimes. When drafting, you should always be gauging the sort of pitching staff you have currently. Whenever you are making your next pick, if you’ve got some upside or volatility already built in, maybe you lean Gonzales. If you’ve already got a solid foundation and you want to see if Eflin can repeat his strikeout ways, then chase him instead.

Let me know where you think I’m off base. Are you targeting any of these five K-BB% gainers in 2021?

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