post

Evaluating Starting Pitchers Using CSW (2018-2019)

The Called-Strikes Plus Swinging Strike rate (CSW) metric developed by Nick Pollack and Alex Fast at Pitcher List is one that takes the next step in analyzing pitchers. We all love K-BB% and that’s a great metric that shows a pitcher’s ability to get batters out without putting the ball in play or vice-versa. The metric takes chance out of the equation such as fielder’s defense, weather conditions, etc. and really shows a pitcher’s skill. Swinging strike rate (SwStr%) also does a great job of showing how good a pitcher is at getting swings and misses. The missing piece is called strikes because not all pitches are created equal. A slider, on average, has a higher swinging strike rate by between 8-9% than a fourseam fastball. A pitcher who can effectively throw a slider 40% of the time will likely have a better SwStr% than a pitcher who relies heavily on his fastball and curveball and doesn’t throw a slider. CSW% accounts for these types of pitchers creating an even playing field.

I’ve looked at starting pitchers who have either increased or decreased their CSW% by at least 2% from the previous year. The minimum qualifiers are at least 1,250 pitches thrown in 2018 and at least 300 pitches thrown this season. Here’s the complete list.

player_nameCSW% Delta
Lucas Giolito5.4
Blake Snell5.1
Derek Holland5
Martin Perez4.8
Matthew Boyd4.8
Carlos Rodon4.7
Caleb Smith4.5
Jake Odorizzi4.4
Stephen Strasburg4.1
Mike Minor4
Felix Hernandez3.9
Luis Castillo3.7
Drew Pomeranz3.7
Tyler Glasnow3.4
Luke Weaver3.2
Tyler Mahle3.2
Kyle Gibson3
Jose Quintana2.9
Eduardo Rodriguez2.7
Lance Lynn2.6
Reynaldo Lopez2.5
Cole Hamels2.4
Trevor Richards2.2
Jake Arrieta2.1
Clayton Kershaw1.9
Dereck Rodriguez-2.3
Joey Lucchesi-2.3
Robbie Ray-2.4
Brad Keller-2.5
J.A. Happ-2.5
Jhoulys Chacin-2.6
Mike Fiers-2.6
Wei-Yin Chen-2.6
Trevor Cahill-2.7
Justin Verlander-2.8
Yonny Chirinos-2.8
Tyler Skaggs-2.9
Zack Godley-3.4
Sean Newcomb-3.4
Dan Straily-4.1
CC Sabathia-4.2
Antonio Senzatela-4.6
Mike Foltynewicz-4.6
Jason Vargas-4.7
Clay Buchholz-4.9
Vince Velasquez-5.2
Nick Pivetta-5.6

Here is the link to the Google Sheet. The first tab shows the pitcher’s CSW% rates form both 2018 and 2019. League average CSW% is 28.7%. You can read more here on the metric. I won’t touch on every pitcher on the list, but feel free to comment and ask me what I think about them going forward.

Risers

I snuck Clayton Kershaw in there even though he’s increased his CSW% by only 1.9% and not the 2% threshold, whoops. It’s enough for me to feel confident that the former best pitcher in baseball will at the very least be productive going forward. His fastball velocity is sitting at a career-low 90.5 MPH but he’s only throwing it 40% of the time. Home runs will be an issue and his strikeout rate won’t be elite, but should still be solid. I’d treat him as a top 15-20 SP going forward.

Lucas Giolito looks like he’s taking the next step in his career. His CSW% was a below-average 26.3% in 2018 and has shot up to a very solid 31.7% this year, nearly elite. The changes seem legitimate too! He’s increased his velocity by over 1.0 MPH on his fastball, completely stopped throwing his sinker, and increased the usage of his changeup. His sinker generated swinging strikes under 5% of the time in 2018, meanwhile, his changeup averages a SwStr% of over 17% and is up to 18.6% this year. He still struggles with control and command and his walk rate remains just over 10%, so he’s not all the way there. That being said, he should be owned in all leagues going forward.

So, Blake Snell is better than he was last year? Well, that’s kind of unfair. Snell won’t repeat his ERA from last season because the ERA-estimators pegged him for an additional 1.10-1.40 runs to his actual ERA. Snell has moved into the top five for starting pitchers for me rest-of-season and maybe top 3.

Luis Castillo is an ace. Not much more to say here. He already was a very good strikeout pitcher last year but has taken his skills to the next level. Unfortunately, I was a year early on Castillo but still fortunate to own him in two places this year.

Luke Weaver is back to where he was in the second half of 2017. He’s throwing his cutter more this year (14.5%) at the expense of his fastball but it isn’t much of an improvement though. It’s his changeup and curveball that have been taken to the next level. The BABIP against his changeup is sub-.200, so that’s bound to come up. I still like Weaver and believe in the improvements, but I do expect some regression in Weaver’s numbers going forward.

Matt Boyd and Caleb Smith are two guys who have both shown some skills before but never could sustain success. Boyd’s issues were more with his fastball and Smith couldn’t stay healthy last year. Both are here to stay, so get used to both of them being inside the top-25 starting pitchers going forward.

Stephen Strasburg no longer throws 97+ MPH but he’s still got a nasty changeup. He’s also throwing more sinkers which has increased his groundball rate. Normally, I would not be a fan of this type of pitch change but it hasn’t hurt his strikeout rate one bit. In fact, his SwStr% is at a career-high 15.6% with a CSW at 34.6% to back it up! If he stays healthy, he’s a top 5-7 option but injuries always seem to find him, so beware.

Ugh, it really sucks that we lost Tyler Glasnow and Carlos Rodon to injuries. Glasnow will likely return this year but we can’t rule out Tommy John Surgery and Rodon has elected to go under the knife. RIP until late-2020 and likely 2021. Both showed great improvements in CSW%, and are still very young, so keep the faith.

Tyler Mahle and Mike Minor both went from having below-average CSW rates to over 30% this year. I absolutely hate their home parks and as the heat rises so could their home run rates. The difference is that Mahle already carries an elevated HR/FB% at over 18% but Minor is sitting at just 10%. Minor also is a fly ball pitcher where Mahle is getting ground balls over 44% of the time. I don’t want to necessarily compare the two but I guess I am. Minor’s HR rate will likely increase and because of his home park, owners will likely need to sit him against tough opponents in Arlington. I feel the same about Mahle though in GAB. If I had to pick one, I’d lean Mahle for the strikeout upside. Either way, both should be owned but will require some maintenance.

Fallers

At the bottom of the list, we have a couple of Phillies. Nick Pivetta and Vince Velasquez. Obviously the popular sleeper, Nick Pivetta is back in Triple-A and VV hit the IL. I don’t want to touch either of them at any point this year, so just stay away.

I’m worried about Mike Foltyneiwicz. I’m willing to give him a little more time because he’s spent some time on the IL, but he was due for some strikeout regression after posting a 30.1% CSW rate last season. Now, he’s just over 25%, which is teetering on poor. There’s a lot of loud contact and fly balls coming off bats against Folty, but you have to hold in 12-team and deeper leagues as you likely spent a top 100-125 pick on him.

Don’t worry about Justin Verlander. He went from a 34% CSW rate to 31.2%. He probably won’t continue to be the number one SP all season but I’d still bet he finishes inside the top five or six. I think Robbie Ray is just fine as well. You know who his is at this point. He will still pile up the strikeouts, give you a decent ERA with an elevated WHIP. Ray is frustrating but has value.

Other than Verlander, Ray, and Tyler Skaggs, I essentially want no part of this group of pitchers except maybe Yonny Chirinos is deeper formats. He’s shown the ability to go as deep as seven innings in a couple of starts and should provide opportunities for wins when an opener is used in front of him. He’s due for some regression with his .205 BABIP but he doesn’t hurt himself with walks either. He needs to get his slider working in order to raise his CSW rate because his splitter is nasty. Skaggs is still intriguing to me. His velocity is down a hair but he’s ditched the sinker in favor of his curve and change. He’s just not getting ahead of hitters as much as he typically does. His first pitch strike rate is down 5% this year. If he rights that ship, his strikeout rate should improve and his ratios with start to drop.

Follow me @FreezeStats. Check out my work at FantasyPros and Pitcher List.


Photo credit: Chicago Tribune