The 2017 Starting Pitcher Walk Rate Regressers by Mike Podhorzer January 26, 2017 Yesterday, I share an updated version of Alex Chamberlain’s pitcher xBB% equation and used it to identify the fantasy relevant pitchers whose walk rates should improve this season. Today, I’ll check in on the other side of the coin, those starting pitchers whose xBB% was well above their actual BB% in 2016. This group will find it challenging to fend off the regression monster this year without throwing more strikes. 2017 BB% Regressers Name Str% K% I/Str 30% BB% xBB% BB%-xBB% Kevin Gausman 64.3% 23.0% 26.6% 5.7% 6.2% 9.1% -2.9% Jake Odorizzi 64.3% 21.5% 25.8% 3.6% 7.0% 8.8% -1.8% Jose Berrios 58.0% 17.4% 28.9% 9.9% 12.5% 14.3% -1.8% Zach Davies 63.9% 19.8% 30.4% 4.4% 5.6% 7.3% -1.7% Chris Tillman 62.0% 19.6% 27.6% 6.4% 9.2% 10.8% -1.6% Gio Gonzalez 61.4% 22.4% 27.6% 3.9% 7.7% 9.2% -1.5% Carlos Rodon 62.8% 23.5% 27.7% 5.6% 7.6% 9.1% -1.5% Jameson Taillon 65.7% 20.3% 30.8% 3.3% 4.1% 5.6% -1.5% League Average 63.8% 21.1% 28.3% 4.6% 8.2% Uh oh, that’s not the name you want to see at the top. Kevin Gausman has generally been a RotoGraphs darling and he made good on his promise in 2016 by posting a 3.61 ERA. But xBB% is skeptical of that 6.2% BB%, which was identical to his 2015 season. Interestingly, Gausman has actually outperformed his xBB% in every season he has been in the Majors. He must be doing something unique we’re not capturing; however, the gap was most significant this year, which no pitcher could sustain. Steamer forecasts a jump to a 7.0% walk rate and I think that may end up being right on the money. Jake Odorizzi continues to post good ERAs thanks to a suppressed BABIP, despite meh underlying skills and an extreme fly ball tendency. He falls in a similar boat to Gausman in that he has also always outperformed his xBB%, but this year was by the most significant degree. A fly ball pitcher will always be fine as long as Kevin Kiermaier is around, but I see far more downside than upside here. I included Jose Berrios‘ name simply to highlight the fact that it actually could have been worse! He already posted a sick 8.02 ERA and pathetic 5.0% K-BB%, but that strike rate is brutal. It actually ranked second worst among starters this season, behind only Jarred Cosart. Besides his control issues, none of his pitches were any good at generating whiffs. It was an all out disastrous debut for Berrios, but he’ll be given more opportunities this year to prove it was simply first year jitters. Baseball Prospectus quantifies command and now suddenly Zach Davies is the talk of the town! Hold your hoses on that bandwagon though, as his walk rate appears headed upward. And don’t try to convince me that this command thing is giving him an edge. Command would still appear in Str%, whether it’s strikes on the edges, stolen strikes off the plate, or strikes right down the middle. A 7.3% BB% is still better than average, but not nearly as intriguing as his actual 5.6% mark. His changeup is fantastic though, which is really the only thing interesting about his skill set in my eyes. I have six seasons of historical Chris Tillman xBB% marks, and guess what? He has outperformed every year. However, in four of the six seasons, the gaps were below 1%, so this year marked the second highest gap of his career. This was also his highest xBB% he’s ever posted. While it appears that he rebounded from his 2015 implosion, there really was just one difference — LOB%, which surged from 68.2% to 77%. He’s never going to find his way onto my team with such an insanely soft skill set. Finally, Gio Gonzalez is the first veteran that hasn’t consistently outperformed his xBB%. This year easily represented the biggest gap , which makes sense because his BB% hit a career low, but his skills didn’t support it. In fact, xBB% suggests his BB% should continue to hover around 9%, which is actually what it had done prior to 2016. Don’t buy the improvement. You might be tempted to point to Carlos Rodon’s big walk rate improvement, while also increasing his strikeout rate, and think big breakout time. Not so fast, as xBB% doesn’t think he deserved all of those steps forward. That said, his slider remains elite, but he really needs better defensive support. It’s going to be a challenge to break out with BABIP marks well over .300. Jameson Taillon, one of the top pitching prospects in baseball, didn’t disappoint during his debut campaign in Pittsburgh. And while his future prospects are exciting, xBB% doesn’t think his control was completely pinpoint, just merely above average. Whatever. His combination of grounders and a 94+ mph fastball is intriguing. Only issue is that his stuff is going to have to induce more whiffs, as it was underwhelming on that front.