Today’s article is inspired by long-time Ducksnorts reader Robby Deming:

Robby raises a good question, which I’ll attempt to answer in a moment. But first, how weak was last year’s Padres bullpen? Acknowledging that ERA is an imperfect representation of reliever performance, here’s how Padres bullpens have fared during the Petco Park era:

Year RP ERA MLB Rank
Padres MLB Season 2004-2012
2004 3.75 4.17 8 87
2005 3.49 4.14 6 50
2006 3.45 4.22 3 44
2007 3.06 4.19 1 15
2008 4.45 4.10 25 208
2009 3.75 4.08 7 86
2010 2.81 3.93 1 4
2011 3.05 3.69 3 14
2012 3.24 3.67 9 28

One problem with ERA can be seen in that third column. Bullpen ERAs over the past two seasons are about a half run lower than they were from 2004 to 2009. So when we say that last year’s Padres ranked 28th out of 270 total bullpens from 2004 to 2012, it’s a little misleading. The standard for relievers has changed over time.

Even still, the bullpen wasn’t bad in 2012. It only seems that way because the 2010 and 2011 versions were outstanding. If you want to see a bad bullpen (and who doesn’t), check out 2008.

The Padres have the lowest bullpen ERA (3.46) in baseball since moving to Petco Park. With more than 4,500 innings and nearly 20,000 batters faced, this is not a small-sample illusion. However, as my pal Lance Richardson notes, it may be a park effect.

No team has a better home ERA than the Padres over the past nine years. Eighteen teams have a better road ERA, including all four of their NL West competitors. So yeah, park effect.

This is all very fascinating, but I still haven’t even started to answer Robby’s question: Which relievers are poised to have a strong year?

Although not all of these guys will start the season in San Diego, most should see action at some point. Again, with the caveats about ERA, here is how they did in 2012 (big leagues only) and how various systems project them to do in 2013:

Player 2012 2013 Projections
BJ OL PE ZI
Brad Boxberger 2.60 3.07 3.62 3.46 3.48
Brad Brach 3.78 3.00 3.25 3.19 3.61
Luke Gregerson 2.39 2.68 2.92 2.96 3.14
Tom Layne 3.24 4.64 4.32 5.04 5.09
Miles Mikolas 3.62 3.60 3.56 4.25 3.93
Huston Street 1.85 2.53 2.59 2.52 2.85
Joe Thatcher 3.41 N/A 3.01 3.30 3.18
Dale Thayer 3.43 3.19 3.15 3.66 3.81
Nick Vincent 1.71 3.07 3.22 3.76 3.74

Key: BJ, Bill James; OL, Oliver; PE, PECOTA; ZI, ZiPS.

The bad news is that most Padres relievers are projected to slip from their 2012 performance. The good news is that projections are often wrong.

The one guy that every system has improving is Brach. I don’t happen to be a big believer in him. Thatcher looks good on paper but has topped 40 innings just once in his career. Mikolas and Thayer are expected to repeat last year’s performance, while everyone else is projected to slip.

But Robby didn’t ask who was going to slip from 2012, he asked who was going to have a strong 2013. Assuming they stay healthy (an unhealthy assumption), I’d say Gregerson, Street, and Thatcher.

Does this answer inspire? I feel like it does not inspire. Oh well, at least it’s honest.

* * *

Who do you like in this year’s bullpen? Leave a comment, send an email (geoff@sonofaduck.com), or hit me up on Twitter (@ducksnorts).

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  • pat

    Heck, GY, it’s Friday, I woke up inspired! Rest at ease, Sir. Your work is done.

  • Thanks Geoff! And looking at the raw numbers, you’re absolutely right. The bullpen only seemed weaker last year in sharp contrast to the previous two seasons.

    I’m kind of surprised that most projections have Street slipping by more than half a run, although I guess we can’t put too much stock in his 2012 numbers given the small sample size.

    Either way, good stuff. I’m so happy to see you writing about the Padres again. Hope I can inspire another post in the future.

    • Geoff Young

      Thanks, Robby; it is good to be back. I only wish I had better news for you. At least we get to watch real games starting on Monday!

  • Where’s Cashner? You know that guy’s not sticking in the rotation.

  • Wow, you do quality, quantative work. I’m digging this Padres Public site. Thanks for informative piece!

    • Geoff Young

      Thanks, Peter, for the kind words! I’m glad you enjoyed it.

  • Lynch Mob

    How about use ERA+ rather than ERA? Doesn’t that account for both ballpark and league effect?

    • Geoff Young

      Good call. It is difficult (for me) to extract ERA+ from the parameters I used, but a decent proxy is (MLB RP ERA)/(Padres RP ERA)*100, which yields the following:

      2004: 111
      2005: 119
      2006: 122
      2007: 137
      2008: 92
      2009: 109
      2010: 140
      2011: 121
      2012: 113

      Although this doesn’t account for park, it gives us a rough idea of the Padres’ bullpen strength relative to MLB for each of those seasons. Thanks for raising the point.

      • Hmmm… not so much a park effect, after all. Also, proof positive that pennants are not won by strong bullpens.

      • Lynch Mob

        I would say a strong bullpen is necessary but not sufficient … but that’s just the scientist-wannabe in me …

        GY … thanks for the calcs …

  • Gloccamorra

    In addition to Cashner, I expect we’ll see Bass, Stauffer, Tyson Ross, and maybe even Marquis and Stults spending some time in the bullpen too. With Luebke and others maybe ready late in the season, the rotation is written on a whiteboard, not chiseled in stone. Better check last year’s Missions relievers who were promoted to Tucson, because they might be called up too.