Thursday, August 03, 2006

4 man rotation

This is a reprint from a month ago. I am very busy today and I think this needs to be said again.

The fifth start should be Bradsisco Santaniano. The Twins should move to a four man rotation and use their best three starters to fill that hole at the fifth spot in the rotation.

There is no reason this can’t be done.OK there are many reasons. One is that Terry Ryan said last week on the radio that “four man rotations have been tried and they have failed.” I thought about this and did not recall the last time it was tried but I thought it was funny that he said it failed.

In the last century of baseball weren’t the majority of years spent by most teams using a four man rotation? Yes. Did it work? Yes. Nobody can tell me that there weren’t any good pitching staffs in last century. I also don’t remember arms falling off.

There is a great article on four man rotations in the book Baseball Between the Numbers. It was put out by Baseball Prospectus. I will be using most of their data and arguments to support my discussion on the Twins use of a four man rotation.

A good quote from the book is “Throwing is not dangerous to a pitcher’s arm. Throwing while tired is dangerous to a pitcher’s arm.” One thing we need to remember is that every pitcher has a different level of fatigue and it is difficult to remember. For some pitchers it may be that they fatigue at 80 pitches and other it may be 140 pitches.

The main argument is that pitchers aren’t tired after three days of rest so why not let them pitch. If it means that a pitcher pitches less per start so be it. It will be more beneficial to the team. But the data shows that most pitched just as long into the game on five man or a four man rotation.

Pitch counts can be helpful in guarding against injuries. It is most important for a pitcher not to pitch when he is tired. That is when his mechanics worsen and he becomes more susceptible to injuries. Pitching on three days rest does not increase the injury chances.

Another argument against using a four man rotation is that a pitcher is less effective on three days rest. This is not true. BP looked at all starters since 1972 who have had at least 8 starts on three and four days rest each.

It was a statistical wash. Their ERA was slightly better on three days rest, walk rates and strikeout rates were nominally worse. The only stat that had changed dramatically at all was the homerun rate. It actually improved 4%. That was the biggest change. So in fact, pitchers were slightly better on three days rest than four.

But what about pitcher that only pitched on three days rest rarely, less than 8 starts in a season. Again it was a statistical wash. But ERA was slightly up.One more objection is that the pitchers will tire at the end of the season, again this wrong. The data shows another statistical wash.The other objection might be that pitchers won’t be able to adjust to the change. Why not? They adjust all of the time. Some starters become relievers or vice verse. They change when they move from the minors to the majors. It happens all of the time.

The last time it was tried it failed. Bob Boone tried it with KC in 1995. It started great but by the end of the season all of the pitchers did indeed get much worse. Maybe this is what Ryan was talking about. So it can fail. But it has work for a century before that. And, most importantly, Boone had his pitchers hit very high pitch counts, sometimes as many 145 pitches.

That is why it failed. Not because of the three days rest. If they were in a five man rotation the chances of these pitchers getting worse as the season went on was just as bad after so many high pitch counts.

So there is no real reason not to have a four man rotation. Then what are the benefits?

First, the worst starter is not pitching in as many games and the best pitchers are now eating up those innings. This will save a great deal of runs in a season.

And there is now an extra roster spot for another hitter.

So how will this affect the Twins? It would give the Twins another 3-5 wins. I base this on three different things. I looked the three pitchers who would take the place of the 5th pitcher, they are Liriano, Santana & Radke. Then I looked at the 5th starter, Silva. I looked at the amount of runs they would give up in 12 games as a guess on how many runs they would give up in that time.

I looked at it three different ways. 1st I looked at total runs against average, 2nd ERA and 3rd I used their FIP. The last way is kind of a guess of how they will pitch the rest of the season.

If all pitchers performed just the same in the 2nd half of the season the amount of runs saved by using Runs Against would be 50 runs. That is five more wins!!! If you just used ERA the four man rotation would save the Twins 44 runs. That is four more wins. If you looked at FIP it would save the Twins about 26 runs. That is about 2-3 wins.

There is no reason to avoid the change to a four man rotation. You would think that an old-school guy like Gardy would want to do this since it is old-school. I will hope they try it but I believe that I have a better chance of passing the Bar exam.

So if at the end of the year we miss the playoffs by three-five games you will know why.


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