Bullpen Observations: Chicago White Sox Relief Pitching


Kyle Terada-USA TODAY Sports

The White Sox have bullpen issues.

I have  said before that the bullpen’s ups and downs combined with an offense Hahn has done a very good job of rebuilding on the fly make the White Sox entertaining in a “no lead is safe and no game is ever over until it’s actually over” way. Here, though, I thought I would try to make sense of why White Sox bullpen roles have settled into their present pattern.

Daniel Rathman of Baseball Prospectus wrote in his What You Need to Know column on Friday, May 23, that bullpen management challenges Robin Ventura because his bullpen is unable to throw strikes and to miss bats. Rathman pointed out that the “White Sox lead the league in reliever walks with 96, 13 more than the second-place Dodgers have issued, and they’ve struck out only 119 batters in 159 innings.”

We can see a bullpen that has improved since April. Their April performance was “disastrous”, though a more diplomatic description is “difficult to watch.” You saw Maikel Cleto didn’t you?

Would-be White Sox closers have been nursing injuries since the beginning of Spring Training, affecting Nate Jones and Matt Lindstrom. Jones hopes to begins physical activity in June following back surgery, and Lindstrom will be out until at least late August following ankle surgery.

The fallout from these injuries resonates through the entire bullpen and complicates Ventura’s decision-making, both within games as well as over longer timeframes as he tries to manage their usage. The White Sox are second in bullpen innings pitched in Major League Baseball pitched in 2014.

At present, Ronald Belisario occupies the closer role for the White Sox despite blowing a three-run lead on Saturday and turning a one-sided 3-0 game on Thursday into a 3-2 squeaker. With 5 earned runs surrendered in his last 2 innings pitched, Belisario has lately provided little relief with his pitching. Since his ascension to the closer role in the wake of Lindstrom’s May 19th ankle injury, Belisario has posted the following line: 3 IP, 8 H, 6 R, 5 ER, 2 BB, 4 K, 0 HR, 15.00 ERA, 4.51 xFIP.

xFIP is predictive of future ERA tendency, as pitchers’ ERAs tend to move from their current ERA figure towards their xFIPs. Generally, the bigger the margin between them, the stronger that tendency. While that tells us Belisario will improve, it should alarm anyone watching this team that “improvement” for this particular short reliever means a 4.50 ERA. But there is more data to parse.

Over the past two weeks the bullpen’s individual members have performed like this (their names link to their game logs at FanGraphs if you wish to see their boxscore lines from each appearance):






































This data tells us the White Sox bullpen has been very good at  not giving up homeruns. Only two teams’ bullpens have lower home runs allowed per nine innings pitched (HR/9) than do the White Sox. Those teams., the Kansas City Royals and the Oakland Athletics, have bullpens generally recognized as great. The White Sox bullpen also has a extremely high groundball rate (55%), trailing only the Sab Frabcusci Giants. If you play your home games in The Cell, you really need as high a groundball rate as possible from you pitchers, especially those working the late innings. Groundballs don’t turn into home runs at the major league level.

The data also tells us the White Sox bullpen issues walks like fast-foot burger joints issue saturated fat. Plate appearances end with a base on balls 8.2% of the time in Major League Baseball in 2014. The White Sox bullpen as a whole has a walk rate of 15.1%. Jake Petricka walks 22.2% of the batters he faces, nearly three times the MLB average, Daniel Webb walks slightly more, 23.1%, of the batters he faces. Scott Downs  walks a sixth (16.7%) of the batters he faces. Frank Francisco performed in a manner that got him designated for assignment. Even Zach Putnam issues far too many walks, as a BB% greater than 10.0 is considered “awful.”

Assuming one does not wish to walk lots of batters in the late innings, one should avoid using pitchers who issue lots of walks in the late inning. That being an obvious truth, it appears the best options for late inning work for the Sox are Ronald Belisario and Matt Lindstrom. Lindstrom is injured.  That leaves us with Ronald Belisario as the best choice for closer.

I know, I wanted to hold my head in my hands and start moaning when I realized this, but there were some things that convinced me this is true, even if disappointing.

The numbers tell us Belisario’s underlying performance is much better than his results have been in the last three games as closer.

He is clearly getting unlucky on balls in play. His line drive rate is only 14%, well below average, which is around 20%. That is significant since the batting average on line drives is slightly over .600; if you give up line drives, you give up a high BABIP.

As much as I didn’t want it to be the case Saturday afternoon, I believe the data tells us Belasario remains the best choice to close given the following four facts; (1) he actually walks a below-average proportion of batters, 7.1%; (2) he strikes out a slightly above-average rate percentage of batters (the MLB K% is 20.1); ( (3) he induces groundballs, sporting the seventh-highest groundball percentage among Major League relief pitchers; (4) the flyballs he allows don’t leave the ballpark, as he has a career 9.9% homerun to flyball rate (HR/FB), which is below the Major League average.

It’s the free passes the other guys give out that make Belisario best suited to close. You might say that him being the best suited to close among the healthy pieces in the bullpen makes him a bit like the Crown Prince of the Island of Misfit Toys.