5-man vs. 4-man rotation

I posted this in another thread and thought it might serve as a decent springboard for some conversation:

I love using a 5-man rotation over/against a 4-man. Part of that is the fact that there are more * SP options and more players go that route, so I'm more likely to get my favorite players with a 5-man. If I'm building a 100M ATG9 team, for example, I may allocate 45M for a pitching staff, and put 4 of that on a closer and another 5 on the other bullpen parts, leaving me about 34M for SP's. (Similar to your estimates, Jim.)

With 34M for SP's, we could do this:

SP1* - Dutch Leonard 12.21M, LH S8 E, 5 BB, 6.75 1B, .28 HR (11.16%, 11.2 total bases)
SP2* - Jacob DeGrom 10.83M, RH S7 4R, 4 BB, 3.75 1B, 1.39 2B vs. RH (8.56%, 9.95 total bases vs. RH)
SP3* - Bob Gibson 7.25M, RH S9* 2R, 3 BB, 10 1B, 1.5 2B, .5 3B, (13.89%, 16.2 total bases vs. RH)
SP4* - Jack Billingham 4.20M RH S8* E, 6 BB, 10.45 1B, 5.05 2B, .5 3B, 2 HR (22.23%, 33.38 total bases)
Filler - 0.50

Total - 34.99M

SP1 - Ferdie Schupp 9.65M, LH S8/R5 E, 7 BB, 4.4 1B (10.55%, 10.55 total bases)
SP2 - Pedro Martinez 8.95M, RH S7/R4 4R, 3.75 1B, 2.64 2B vs. RH (6.39%, 9.04 total bases vs. RH)
SP3 - Willard Schmidt 6.43M, RH S9/R3 3R, 10 BB, 1.62 1B, 1.94 2B, 0.6 3B (13.38%, 16.44 total bases vs. RH)
SP4 - Bobby Bolin 5.44M, RH S8 1L, 6 BB, 8 1B, 4.9 2B, .2 3B, 1 HR (18.63%, 26.34 total bases)
SP5 - Andy Cooper 4.02M, LH S8/R1 E, 6 BB, 11.25 1B, 6 2B, 1 3B (22.47%, 29.89 total bases)

Total - 34.49M (saving the price of the filler piece)

The 5-man vs. 4-man argument is a qualitative decision based on the number of starts. With a 4-man, you get 40 starts each from everyone with 41 for your 1-2. With the 5-man, it is 32 starts per (with 33 to 1/2). Dropping 8 starts each from Leonard, DeGrom, and Gibson and giving those to Bobby Bolin/Andy Cooper is a HUGE downgrade in those 24 games. However, taking all 40 of Billingham's starts away and distributing them between Bolin/Cooper is an upgrade (not as much of an upgrade as the downgrade). And then you have Schupp/Martinez/Schmidt being marginally better in all of their 32 starts than the 32 starts from the top 3 SP* guys ...

Fun times!

I generally prefer the 5-man. But that's the math. It's pretty darn close.

I, too, often use a 5-man rotation for the reasons you mention. Another advantage is you can draft some of your starters a bit lower in your draft list since there is usually little demand for them. Of course, this can all backfire if another manager goes this route and suddenly you don't get your key starters.

My number one reason for using a 4-man rotation is that I don't have to worry about injuries causing anyone to miss a start.

I have done some analysis using expected OBA and have not found a 5-man combination that would be cheaper that a 4-man for the same OBA.

My number one reason for using a 4-man rotation is that I don't have to worry about injuries causing anyone to miss a start.

I have done some analysis using expected OBA and have not found a 5-man combination that would be cheaper that a 4-man for the same OBA.

What does your expected OBA indicate about the rotations proposed above?

My number one reason for using a 4-man rotation is that I don't have to worry about injuries causing anyone to miss a start.

I have done some analysis using expected OBA and have not found a 5-man combination that would be cheaper that a 4-man for the same OBA.

What does your expected OBA indicate about the rotations proposed above?

The 5 man rotation in this example would be slightly better than the 4-man. But most of the 4 man rotations I use would be lower than both of these examples and some with a lower cost. My quick take was using a pitchers ball park.