Which bullpens have been worked the hardest in 2013?

Is there reason to worry about Jason Grilli and the Pittsburgh bullpen?
Is there reason to worry about Jason Grilli and the Pittsburgh bullpen? USATSI

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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 ...

NumTeamRelief-IPTBFPitchesSL% (pfx)CU% (pfx)
1 Pittsburgh Pirates 164.3 675 2725 21.4 % 5.1 %
2 San Francisco Giants 141.6 607 2292 29.9 % 3.8 %
3 Atlanta Braves 123.2 512 1990 14.5 % 6.9 %
4 Oakland Athletics 149.8 631 2547 22.7 % 10.0 %
5 Colorado Rockies 162.0 684 2600 25.2 % 1.7 %
6 Kansas City Royals 106.9 447 1820 13.2 % 15.6 %
7 San Diego Padres 157.9 649 2601 27.6 % 3.5 %
8 Arizona Diamondbacks 131.6 551 2068 8.7 % 13.6 %
9 New York Yankees 139.2 583 2281 20.5 % 9.7 %
10 Texas Rangers 134.7 574 2172 19.6 % 4.6 %
11 Minnesota Twins 160.9 682 2615 14.3 % 12.8 %
12 Cleveland Indians 145.4 621 2474 19.4 % 8.5 %
13 Milwaukee Brewers 146.8 617 2407 24.2 % 5.8 %
14 Cincinnati Reds 131.5 552 2211 17.4 % 7.9 %
15 Baltimore Orioles 150.4 656 2563 23.2 % 4.3 %
16 Toronto Blue Jays 162.0 704 2632 17.7 % 8.1 %
17 Detroit Tigers 138.0 592 2412 23.8 % 2.2 %
18 Seattle Mariners 139.6 590 2307 14.9 % 18.7 %
19 Washington Nationals 124.6 546 2147 15.4 % 3.6 %
20 Miami Marlins 151.4 660 2559 23.4 % 5.8 %
21 Chicago White Sox 126.7 561 2224 22.1 % 7.5 %
22 Chicago Cubs 120.9 533 2037 32.4 % 1.3 %
23 Boston Red Sox 138.2 610 2434 17.7 % 4.3 %
24 Los Angeles Dodgers 130.1 584 2334 17.8 % 4.6 %
25 Los Angeles Angels 149.7 667 2637 14.0 % 4.0 %
26 Philadelphia Phillies 116.8 520 2003 14.7 % 12.1 %
27 St. Louis Cardinals 114.8 513 1940 10.2 % 5.2 %
28 New York Mets 146.0 635 2411 24.0 % 4.6 %
29 Tampa Bay Rays 121.1 541 2137 9.1 % 9.2 %
30 Houston 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.

CBS Sports Writer

Dayn Perry has been a baseball writer for CBS Sports since early 2012. Prior to that, he wrote for FOXSports.com and ESPN.com. A member of the BBWAA, He's the author of three books, the most recent being... Full Bio

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