Optimal Pitching Roster Construction

One of the unique things about fantasy baseball is that there is a lot more diversity in league formats than there is in fantasy football. While I’ve been playing fantasy football for over a decade, I’m relatively new to the world of serious fantasy baseball, so as I’ve gotten ramped up to the format recently I’ve had to learn some lessons about how to construct a roster. This post is a discussion of how to construct an optimal pitching staff in a head-to-head points league that has SP and RP caps but no innings cap. All stats I reference from here on are season-to-date as of May 26th 2023.

What can you expect from starting pitching?

One of the nice things about a starting pitcher relative to a reliever is that they don't use a roster spot unnecessarily. That is, you know what days they're going to pitch- some days you insert a reliever into your lineup only for him not to pitch, and leave a reliever who does pitch on your bench.

A healthy starter will give you 1.2 starts/week (they will make 32 starts over the course of the season and the season is 185 calendar days).

Here are some benchmarks for points/start among starting pitching.

SP1 (Shane McClanahan) 18.8 points/start

SP10 (Framber Valdez) 16.6 points/start

SP25 (Jon Gray) 13.9 points/start

SP50 (Hunter Greene) 9.5 points/start

There are loads of guys on the waiver wire averaging 7 points/start. I think that by playing the matchups well you can get 8 points/start out of the waiver wire.

What can you expect from relief pitching?

Here are some benchmarks for point/appearance among relief pitching. Keep in mind that appearances are tougher to predict for relievers than starters.

RP1 (Felix Bautista) 6.5 points/appearance

RP10 (David Robertson) 5.7 points/appearance

RP25 (Andrew Chafin) 3.8 points/appearance

There are loads of relievers available who average 3.5-4 points/appearance.

The value of streaming

From these figures we can come up with some hard numbers on the value of streaming. Suppose your options are to roster a decent starter, around SP40 or so- you can bank on him getting around 11 points/start, and making 1.2 starts/week, making him worth 13.2 points/week. If instead, you use that roster spot to make 5 streams at 8 points/stream, that roster spot is worth 40 points/week, triple what you get from a decent starter. A streaming starting spot is the single highest scoring spot on your roster- more than you'd expect from Shane McClanahan (~22 points/week) or Freddie Freeman (~24 points/week). The problem, of course, is that it costs a very valuable resource- roster moves. Choosing not to stream because you want to keep a mediocre pitcher on the roster is a fool's errand- every week you do this, you are burning about 25 points/week.

The value of RP/SP

This brings me to my final topic- the famed RP/SP position. A RP/SP who starts is valuable because, unlike other relievers, you can predict when he will pitch and only start him accordingly. A replacement-level starter who has an RP/SP designation is worth 8 points/start * 1.2 starts/week = 9.6 points/week, although you do have to pay the opportunity cost of not using a proper reliever that day, which I value at approximately 1.2 times/week * 70% chance of reliever being used * 4 points/relief appearance = 3.4 points/week. Therefore, having a crappy guy as an RP/SP is worth an additional 6 points per week. 6 points per week may not sound like a lot, but that's also the difference between a hitter who gets 3 points/game and a hitter who gets 2.2 points/game, which we know to be a tremendous difference.

A quick side note- because Shohei Ohtani does not count against the SP cap, but like an RP/SP is predictable when he will pitch, he also gets this benefit. I believe this fact makes Ohtani by far the most valuable asset in this scoring system.

Optimal Roster Construction

Given our constraints of 8 SP and 4 RP maximums, I think that the optimal way to construct a staff is as follows:

7 traditional SP who you do not drop- 8.4 starts/week at 13 points/start = 109 points/week. 13 points/start is equivalent to approximately SP35.

1 SP spot for streaming- 5 starts/week (I'm assuming you use 1 roster move/week on a hitter) at 8 points/start = 40 points/week

2 RP/SP- 1.2 starts/week at 8 points/start = 19 points/week

2 traditional RP- 3 appearances/week at 5 points/appearance = 30 points/week

In total, this gives 203 points/week from one's pitching staff if correctly managed, and this is only assuming average starting pitching. Good roster management (streaming and the RP/SP trick) take your pitching staff from 144 points/week to 203 points/week.