We'll soon be one-third of the way through the 2013 MLB season, so why not check in on the various bullpens and see which are being leaned on perhaps too heavily?
The table to follow, which comes to us courtesy of the nifty custom leaderboards over at FanGraphs, will list for each team relief innings pitched, total batters faced by relievers and total pitches thrown by relievers. As well, we'll also list each bullpen's percentage of sliders (SL%) and curveballs (CU%), per Pitch F/X data. That provides us with a quick-and-dirty estimate of which bullpen has thrown the largest proportion of high-stress pitches. To state the obvious, there's nothing inherently wrong with relievers' leaning on their breaking stuff, but a high rate of such wrist-snapping pitches can contribute to the overall fatigue profile.
And now to the numbers ...
|Num||Team||Relief-IP||TBF||Pitches||SL% (pfx)||CU% (pfx)|
|1||Pirates||164.3||675||2725||21.4 %||5.1 %|
|2||Giants||141.6||607||2292||29.9 %||3.8 %|
|3||Braves||123.2||512||1990||14.5 %||6.9 %|
|4||Athletics||149.8||631||2547||22.7 %||10.0 %|
|5||Rockies||162.0||684||2600||25.2 %||1.7 %|
|6||Royals||106.9||447||1820||13.2 %||15.6 %|
|7||Padres||157.9||649||2601||27.6 %||3.5 %|
|8||Diamondbacks||131.6||551||2068||8.7 %||13.6 %|
|9||Yankees||139.2||583||2281||20.5 %||9.7 %|
|10||Rangers||134.7||574||2172||19.6 %||4.6 %|
|11||Twins||160.9||682||2615||14.3 %||12.8 %|
|12||Indians||145.4||621||2474||19.4 %||8.5 %|
|13||Brewers||146.8||617||2407||24.2 %||5.8 %|
|14||Reds||131.5||552||2211||17.4 %||7.9 %|
|15||Orioles||150.4||656||2563||23.2 %||4.3 %|
|16||Blue Jays||162.0||704||2632||17.7 %||8.1 %|
|17||Tigers||138.0||592||2412||23.8 %||2.2 %|
|18||Mariners||139.6||590||2307||14.9 %||18.7 %|
|19||Nationals||124.6||546||2147||15.4 %||3.6 %|
|20||Marlins||151.4||660||2559||23.4 %||5.8 %|
|21||White Sox||126.7||561||2224||22.1 %||7.5 %|
|22||Cubs||120.9||533||2037||32.4 %||1.3 %|
|23||Red Sox||138.2||610||2434||17.7 %||4.3 %|
|24||Dodgers||130.1||584||2334||17.8 %||4.6 %|
|25||Angels||149.7||667||2637||14.0 %||4.0 %|
|26||Phillies||116.8||520||2003||14.7 %||12.1 %|
|27||Cardinals||114.8||513||1940||10.2 %||5.2 %|
|28||Mets||146.0||635||2411||24.0 %||4.6 %|
|29||Rays||121.1||541||2137||9.1 %||9.2 %|
|30||Astros||173.9||790||3002||12.3 %||14.9 %|
And now, some obervations ...
- It's hardly surprising to see teams like the Astros, Twins, Blue Jays and Padres high on the bullpen innings list -- their rotations have been pretty bad thus far, and bad rotations yield high bullpen workloads.
- Pity the Houston relievers. They've faced 86 more batters than the next-closest team, and they've thrown 277 more pitches than the next-closest team. The Astros are going to cycle through a lot of relievers in 2013 (they've already used 11 of them thus far).
- The Cubs' bullpen, which hasn't been very effective thus far, leads the majors in sliders as a percentage of total pitches -- 32.4 percent. That's a lot of stress on those relief arms thus far.
- The Giants aren't far behind the Cubs in terms of slider percentage (29.9 percent), and they're tied with the Cubs for the lead in overall percentage of breaking balls (33.7 percent). As well, the Giants' pen has been worked significantly harder than the Cubs', and the Giants, unlike the Cubs, have designs on contention. Worth monitoring.
- Another contending bullpen to worry about is Pittsburgh's. Pirate relievers thus far in 2013 have been outstanding -- they lead all of baseball with an ERA of 2.74 -- but they rank second in pitches thrown and innings and fifth in batters faced. Can the Bucco bullpen continue shouldering that kind of workload and also continue being one of MLB's best?
- Other contending/contending-ish bullpens that might bear watching in terms of usage: Rockies (nothing unusual for the denizens of Coors Field), Orioles, Athletics, Blue Jays and Angels.
- More good news for the Cardinals: Their bullpen has had it relatively easy. St. Louis relievers rank 29th in pitches, 28th in batters faced and 29th in innings. Additionally, no team's bullpen has thrown a lower percentage of breaking balls than the Cardinals' pen, which checks in at 15.4 percent.
The big takeaways: The Pirates may be poised to see some key relievers hit the wall down the stretch, while the Cardinals, should trends hold, may wind up with the freshest bullpen of all -- both in terms of overall usage and their relatively low-stress pitch selection.