K/BB, K/9-BB/9, and Save Situations
August 31, 2008 4 Comments
As I watched Brad Lidge shut down the Cubs in the ninth innings on both Saturday and Sunday, it dawned on me why my confidence level soars through the roof every time he enters a game in a save situation. It isn’t solely because he is yet to blow a save, or because he throws with high velocity, but rather because he does not walk many batters and he strikes out a ton of them. To me, this results in a very easygoing ninth inning experience, unlike the ones I experienced with Tom Gordon over the last couple of years.
Other fans may desire different attributes amongst their closers, but I just want the least amount of stress possible. In theory, as long as we assume that balls in play are random, a closer that does not walk many hitters and strikes out plenty would fit this least-stress bill. No, nobody has a 0.00 BB/9 and 27.00 K/9 but within reasonable terms the low BB/9 and high K/9 is what would interest me. In evaluating closers during save situations in my database, and after hearing the thoughts of some fans with regards to the K/BB ratio, I wondered if it would make a difference if, instead of dividing strikeouts and walks, we subtracted?
Keep in mind that I am in no way endorsing either as the gold standard but rather wondering if it makes a difference. One opinion I read on a forum, which was seemingly derived from one of Ron Shandler’s fantasy plans, stipulated that subtracting the BB/9 from K/9 would give a better view since the K/BB ratios can come in all shapes and sizes–a 2.50 K/BB with a 5 K/9 and a 2 BB/9 is different than one with a 9.00 K/9 and a 4.00 BB/9. Another thought was simply to use the K/BB but set a minimum for the K/9; as in, consider any K/BB above 2.50 to be very solid as long as the K/9 exceeded 6.0.
Normally, I would jump at an opinion like this and call it poppycock because a starter can be successful with under 6 K/9 if his K/BB is great; the 6.0 minimum is essentially artificial. However, when looking at which closer offers the least stressful outings in terms of controllable skills, might there be some credence to looking at K/BB in a different light? John Rocker, in 1999, in save situations, struck out 15.70 batters per nine while walking 4.97. His K/BB was 3.16, good, but not tremendous given his ridiculous K/9. In 1994, Robb Nen had a 10.43 K/9 and a 1.74 BB/9 during save situations, a 5.99 K/BB.
The K/BB would lead us to believe that Nen was much more effective, but the K/9-BB/9 would suggest that a case could be made for Rocker. The advantage he has in K/9 is greater than Nen’s BB/9 advantage. Again, this isn’t something I would support in any instance other than perhaps evaluating closers in save situations. Subtracting the BB/9 from K/9 would give us an idea of how both metrics are related to one another while also accounting for the fact that striking out batters as a closer is, well, a really good trait. Looking solely at save situations, here are the top ten seasons in K-BB, from 1980-2007, with a minimum of 15 saves:
- Eric Gagne, 2003: 13.89 (15.47-1.58)
- Billy Wagner, 1999: 12.60 (15.36-2.76)
- Brad Lidge, 2004: 12.22 (14.92-2.70)
- Takashi Saito, 2006: 12.00 (14.00-2.00)
- Joe Nathan, 2006: 11.39 (13.40-2.01)
- Tom Henke, 1989: 11.36 (12.49-1.13)
- Troy Percival, 1997: 11.17 (14.59-3.41)
- Billy Wagner, 1998: 11.15 (14.78-3.63)
- Eric Gagne, 2002: 10.90 (12.54-1.64)
- Robb Nen, 2000: 10.84 (14.11-3.27)
There were actually 15 seasons in which a closer met the aforementioned criteria and posted a negative K-BB, meaning that they walked more than they fanned. Based on this, the worst and most stressful closed season in this span belongs to the 1984 season of Doug Sisk, with his -2.34 mark. Curious to see whether or not this stat made a difference, I ran correlations between K-BB and both ERA and OPS against, and K/BB with the same two comparative metrics. The results:
- K-BB: -0.28 to ERA, -0.40 to OPS against
- K/BB: -0.29 to ERA, -0.37 to OPS against
Essentially, this tells us that it really does not make a difference if we use K/BB or K/9-BB/9. Regardless of whether or not the K/BB ratio accounts for the fact that K/9 and BB/9 come in all shapes and sizes, their relationships with ERA and OPS against are virtually the same. If setting a minimum K/9 for your starter helps in a fantasy league, go ahead, but in evaluating players in a non-fantasy setting, the minimum is artifical and K/9-BB/9 makes no difference.