In case you've been on the moon or busy watching soccer there has been some discussion in Dodgers-Land about whether or not to skip Ricky Nolasco in Game #4 of the NLCS or bring back Zack Greinke to pitch on short rest. I decided to take a back of the envelope look at which decision is the correct way to go. My exercise won't go into the nitty-gritty details which would add a little more precision to the numbers but it will provide a good framework and maybe some guidance into what the best decision is.
In general there is a 0.5 RA/9ip penalty for pitching on three days rest and there is probably a little penalty for pitching on too many days rest but let's leave that number unknown for now. What I did is made a table with the RA/9 expectancies for each of the Dodgers four starting pitchers. Then output tables showing which starting pitching arrangement looks best. The RA/9ip estimates can be changed if you don't agree with them, this is just the framework and with the framework you can tell how bad of a pitcher Nolasco must be to make skipping him and starting Greinke (and even perhaps Kershaw and Ryu) on short rest.
Now let's come up with some rotation arrangements. Let's first start off with the one where Nolasco pitches Game #4 and Greinke, Kershaw and Ryu all pitch on regular rest.
Now let's see what happens if Nolasco is skipped and Greinke (G4, G7), Kershaw (G5) and Ryu (G6) all pitch on short rest. Notice the 0.5 RA/9ip penalty applied.
This particular arrangement does not fair too well as you are applying four 0.5 RA/9ip penalties, adding up to 2.0 RA/9ip over four games. Nolasco's projection MUST be very very bad for this option to win out. How bad? I will visit that later.
Now onto the arrangement where Zack Greinke pitches Game #4 on short rest then Nolasco pitches Game #5 and Kershaw and Ryu pitch the last two games on full rest. I call this the "Rearranging The Deck Chairs" option.
This option always loses out to the first option as you are just swapping Game #4 and Game #5 starters and adding a penalty to Greinke's start. This option is stupid.
So it comes down to the first two options and the first option will win out unless you think that Nolasco is a terrible pitcher. Just how terrible in terms of RA/9ip? And you can feel free to combine Nolasco's RA/9ip with that of Volquez if you think they will tag team their start. Only good thing about that is that you can get an early pinch hitter at-bat in the game. But let's get back to the question of how bad would Nolasco's RA/9ip projection have to be to make the second option a better one than the third. The break even point for Nolasco's RA/9ip projection is 5.0. If you think his RA/9ip projection is worse than 5.0 then the second option would be better and you would go with a three man rotation. Of course there are some other minor things to take into consideration, so you could add or subtract those in to the RA/9ip projections but this exercise gives you an idea for which rotation arrangement is best.
I think the Dodgers should start Nolasco and if he isn't terribly sharp or being hit hard to pinch hit for him in either his first or second at-bat and then to use Volquez until he bats and then to let the bullpen finish out the game. Hopefully, you won't go extra innings as you will be using a lot of your bullets early on in the game.