Saturday, June 14, 2014

Measuring the Tigers Bullpen Woes

In a recent post, I used the RE24 statistic to measure batting contribution including situational hitting.  The statistic is appealing because it gives batters more credit for hits with runners on base than for hits with the bases empty.  This concept can also be applied to pitchers, relievers in particular.

Statistical evaluation of relievers is difficult for a couple of reasons:
  1. They pitch so few innings that their statistics can be influenced heavily by a couple of really bad outings.
  2. Their actual value depends on game situations more than any other player (this problem will be addressed here)
Using ERA to evaluate relievers is problematic because relievers often make appearances with runners on base and give up other pitcher's runs. So, a pitcher could have a low ERA without actually being that effective. FIP ERA which is based on walks, strikeouts and home runs allowed rather than runs allowed is better but it still does not consider the game environments in which a reliever pitched.

The RE24 metric estimates the number of runs a pitcher saved or cost his team based on his numbers of singles, doubles and all other events allowed including outs.  It also considers the situations in which these events happened.  For example, if Tigers southpaw Ian Krol enters a game with two men on base and nobody out and retires the side he will get more credit than if he comes in with the bases empty.  Krol gets more points in the first scenario because there was greater potential for run scoring.  Thus, Krol saves the Tigers more runs if he frequently pitches well with runners on base than if he always starts an appearance with the bases empty.

The RE24 for all American League teams is shown in Table 1 below.  The Tigers have an RE24 of -12.8 which says that their bullpen has cost them an estimated 13 runs compared to an average staff with the same number of outs. The interpretation is a little misleading because the average also includes starters.  However, all bullpens are compared to that same average, so the ranks are telling and only the Astros (-15.2) and Rangers (-16.8) have been worse than the Tigers.  

Table 1: RE24 for American League teams, June 13, 2014
Team
RE24
Athletics
35.3
Red Sox
29.2
Mariners
24.2
Orioles
13.7
Indians
7.1
White Sox
6.0
Royals
5.1
Blue Jays
4.1
Twins
0.8
Rays
-0.2
Angels
-2.6
Yankees
-6.0
Tigers
-12.8
Astros
-15.2
Rangers
-16.8
Data source: FanGraphs.com

The American League RE24 leaders among relievers are shown in Table 2 below.  New York Yankees right hander Dellin Betances leads the league with a RE24 of 13.2.  The Athletics have three pitchers in the top 15 - Fernando Abad (12.1), Dan Otero (9.1) and Sean Doolittle (8.4) - which is not surprising since Table 1 showed that their team RE24 is best in the league.   

Table 2: AL RE24 Leaders Among Relievers
Name
Team
RE24
Dellin Betances
Yankees
13.2
Koji Uehara
Red Sox
13.1
Zach Britton
Orioles
13.0
Fernando Abad
Athletics
12.1
Jake McGee
Rays
12.0
Burke Badenhop
Red Sox
11.7
Dustin McGowan
Blue Jays
9.9
Zach Putnam
White Sox
9.9
Wade Davis
Royals
9.9
Darren O'Day
Orioles
9.7
Aaron Loup
Blue Jays
9.6
Dan Otero
Athletics
9.1
Sean Doolittle
Athletics
8.4
Casey Fien
Twins
7.5
Adam Warren
Yankees
7.4
Data source: FanGraphs.com

Table 3 shows that right hander Al Alburquerque leads the Tigers with a 5.7 RE24 and that Joba Chamberlain (3.6) and Evan Reed (2.3) also have positive values, but none of them are close to being among the league leaders.  Closer Joe Nathan is one of the worst in the league at -8.0 which surprises nobody.     

Table 3: RE24 for Tigers Relievers
Name
RE24
Al Alburquerque
5.7
Joba Chamberlain
3.6
Evan Reed
2.3
Ian Krol
-1.6
Phil Coke
-3.7
Joe Nathan
-8.0
Data source: FanGraphs.com

So, does this mean that the bullpen is destroying the Tigers season?  Well, they are 29-4 when they lead after the sixth inning and this 88% rate is marginally better than the MLB average of 87%.  The Tigers have blown three leads when leading after the eighth and we can blame Nathan for that, but that's only one worse than the average team which has blown two games after the eighth.  

On the other hand, the Tigers are 2-6 when tied after six innings and the bullpen has to take some of the responsibility for that.  So, while the bullpen is not dooming the season as much as it may seem, it is certainly hurting the team and it's an area that needs to be addressed as the season progresses.

4 comments:

  1. Well let's look at the glass half full for a moment just because...we are still in 1st place despite this bad stretch from the RP group, but if we do indeed win the division then this full group will have a fresh start since the sorting of data in the future for the heading of "postseason" from "regular season" is going to be the biggie table that we all really care about the most, and that could be anywhere from first to worst. So if we can still be in 1st place at this point, then odds are the RP group can't get much worse to make it any harder for the rest of the season, and even our bats have potential to do better than average so far to help shore up the odds to still win the division.

    And of course the downside is simply still not winning the WS and then having more dead money across our entire roster that could have been displaced to spruce up the future.

    Our fate is still yet to be determined, but the unfortunate thing is that our risk/reward profile is still poorly leveraged as a franchise and there's no escaping that conundrum without serious attitude changes coming from the Ownership.

    But great to see the studly performance by Scherzer the other day, that was awesome!

    ReplyDelete
    Replies
    1. Oh and I for one love replay-review HRs. I hope the World Series ends this year with a walk off replay, that would be sweet justice for whoever it happens for!

      Delete
  2. The "magic spell" this team needs is an Owner who will bring in a top-flight GM to make things right.

    ReplyDelete
  3. AnonymousJune 23, 2014

    Have you checked out the team totals for the Tigers wRAA and RE24 from 2011-present with this fairly similar hitting core? They under perform every year and this year has been no different.

    From 2011-2014, they lead MLB with a wRAA of 349.5. However, they are 4th in RE24 at 152.87.

    Anyway, its an idea for a future study or something to look more in-depth on.

    ReplyDelete

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