http://www.startribune.com/sports/twins/34051374.html?elr=KArksi8cyaiUqCP:iUiD3aPc:_Yyc:aUU

After the Twins were eliminated by the White Sox, fans everywhere began to gripe about the coin flip that forced the Twins to play the White Sox in Chicago - even though the Twins won the season series 10-8. Every writer and broadcaster told the fans to shove-it, stop whining, “that’s the system and it won’t change because…etc. etc.”

Well, it seems the fans had a point - the coin flip needs to go.

Defense has 2 factors:

a. accuracy - reflected by Errors. Errors do not count on WHIP, so that is out.

b. range - let’s use the plus minus system for this to understand the impact:

in 2008 the best defender in baseball as far as plus-minus goes was Chace Utley with a total score of 49 (i.e. he made 49 plays the average player does not make). He made a total of 803 plays (340 POs and 463 assists) even if we assume that all those +49 plays took a hit away (which is a stretch, because some of those were to get the lead runner in a double play or fielder’s choice, both of which do not take hits away from a pitcher’s WHIP).

49 is 6.1% of his total plays. If you divide that by 5 starting pitchers you get 1.2%.

So the best defender in baseball saved 1.2% of the hits for a particular starting pitcher (stretch). If you take the MLB average for 2008 pitchers 0.37 BB/Hits, 0.37 of a pitcher’s WHIP is a factor of BB and 0.73 a factor of hits. So the difference that the best ranging defender can potentially make on a pitcher’s WHIP is 0.88%

With examples:

Perkins’ WHIP in 2008 was 1.470, in that theoretical best case scenario would have been 1.457

Let’s go more extreme: here are the best plus minus numbers per position in 2008 (2B was Utley): 1B +24, 3B + 32, SS +23, LF +23, CF +32, P +16.
If you build a team with those people as defenders, the 0.88% difference above due to just Utley would become 3.6%

In other words, Perkins with the best defense in the MLB Universe of 2008 would have a WHIP of 1.417 instead of 1.457 (even with the best case scenario that all plus plays take hits away).

Not much difference

I think you are understating the effects of defense and overstating the effects of management. Either way, my point was that WHIP is not immune to factors that are beyond a pitcher’s control.