I don’t discuss it as often as my xK% equation, because the R-squared is significantly lower, but my xBB% formula is still useful to calculate and analyze the results. Even for hitters, strikeout rates have always been easier to predict from an equation than walk rates. Odd. Anyway, let’s take a look at the four starting pitchers whose xBB% marks are most below their actual walk rates. This could signify improvement on the way, which would bring both ERA and WHIP down.
John Lackey | 5.6% BB% vs 2.4% xBB%
Lackey’s 2.4% xBB% is third lowest in baseball, behind strike throwing machines Bartolo Colon and Phil Hughes. His strike percentage has risen for the fourth straight season, which is what you want to see from an aging veteran whose stuff probably isn’t as good as it used to be. He’s also pumping in first pitch strikes at a career high rate nearing 70%. That ranks fourth among qualified starters.
Lackey is the perfect example of an undervalued veteran whose in a perfect situation to earn his fantasy owners a tidy profit. He calls a pitcher’s park home and is supported by an excellent defense. His slider/cutter remains fantastic, inducing both swings and misses and ground balls when batters do manage to make contact. He should continue to remain well above replacement level in 12-team mixed leagues and xBB% suggest he actually has a bit of hidden upside from here.
Matt Garza | 8.7% BB% vs 5.8% xBB%
Fly balls have not been kind to Garza this season as 15.5% of them have left the ball park, resulting in an inflated 4.80 ERA. He has never posted an ERA above 3.95 in a full season. And while a decline in strikeout rate backed by a dipping in swinging strike rate dims our hopes for a major rebound, a career best rate of strikes thrown does provide some optimism. Garza has never actually posted a walk rate below 6.4%, and that was the only time it sat below 7.4%, so just looking at his history suggests a significantly improvement is unlikely to be in the cards.
But remember that this isn’t the same pitcher he has been. He’s both throwing more strikes than ever before and also allowing more balls put into play. The latter isn’t exactly a good thing, but a ball in play does mean that the batter isn’t walking. So Garza’s fastball velocity is the same as last year and his pitch mix quite similar. The difference is that his once fantastic slider has really lost its effectiveness. If he could rediscover it and cut his walk rate like his xBB% hints at, then he should perform much better over the rest of the season.
Anthony DeSclafani | 9.3% BB% vs 6.7% xBB%
DeSclafani was a favorite deep sleeper heading into the season. Over his first four starts, he made his fans look like geniuses, as he allowed just three earned runs over 26 innings. Since then (excluding last night), the wheels have come off, and his ERA is approaching 5.00. But the good news is that aside from his short stint at Triple-A back in 2014, DeSclafani has displayed much better control. Or at least posted better walk rates. Because at the moment, xBB% thinks his control should be leading to a significantly lower walk rate.
But even if that walk rate does come down, we’re still left with a pitcher who owns a ghastly 4.73 SIERA. No amount of walk rate improvement is going to make that SIERA palatable unless he suddenly decides to issue zero free passes the rest of the way. But there’s some hope, at least for more strikeouts. Both his slider and four-seam fastball have induced swinging strikes at rates well above the average. His changeup hasn’t been great, but it has remained acceptable enough to continue throwing about one of every 10 pitches. The curve ball might as well just be scrapped. He has thrown only 23 of them so far, but has yet to induce a swinging strike. The future road map for improvement would be to up his slider usage a notch at the expense of his two-seamer, a pitch that should only really be thrown if a ground ball is required, and stop throwing curve balls, period.
Given the disparity between his SIERA and ERA, there’s still more downside to go even if he does improve his skills. But if that downside occurs in short order (and it could have happened last night after I finished typing this), then we won’t have to worry about further ERA regression and can just look forward to skills progression.
Shelby Miller | 8.0% BB% vs 5.9% xBB%
Miller has become a completely new pitcher this year, as he has significantly upped his usage of the cutter at the expense of both his fastball and curve and has thrown more two-seamers, rather than four-seamers. It has resulted in a marginal rebound in strikeout rate, but more importantly, a huge spike in ground ball rate. His overall skill set has improved and he has gotten his SIERA back to between his 2013 and 2014 mark. Of course, serious good fortune in all three luck metrics have kept his ERA near 2.00, where it’s not going to stay for much longer.
But might there be some skill set improvement to offset some of the ERA regression we know is coming? His xBB% suggests that may be the case, but I noted that last year he also sported a significantly lower xBB% than actual BB%. Interestingly, both marks were about the same back in 2013, so there’s not a long history here of underperforming his xBB%. As such, I would bet on xBB% here as his strike percentage has jumped from his first two full seasons. Still, it’s not going to matter much once the hits start falling in, the fly balls start flying over the wall and he’s suddenly unable to strand over 80% of runners. He’s as obvious a sell high candidate as there is.
Mike Podhorzer is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year. He produces player projections using his own forecasting system and is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. His projections helped him win the inaugural 2013 Tout Wars mixed draft league. Follow Mike on Twitter @MikePodhorzer and contact him via email.