Why a replacement-level player isn’t valuable
January 10, 2009 20 Comments
An arguement that I continue to encounter is that the replacement-level player still has some value to a team – that he has real hits and home runs, and that those still contribute to real wins in some way. Viewed in this light, it’s silly to say that a replacement-level player has no value. Isn’t it?
What we want to look at is the full universe of a team’s options – not just guys who have played in the majors, but guys that could play in the majors — roster filler at AAA, prospects at AA, and free agents looking for so much as a minor league invite. So for that, we’ll use Rally’s CHONE projections, which looks not only at major leaguers but a whole slew of minor leaguers.
This is an illustration, and not a study – so I used Rally’s R150 to estimate runs, and his projected playing time measured in AB. I also ignored defense. If we wanted to study the issue in-depth we could tighten up a lot of assumptions there.
So let’s look at the graph:
The x axis is R150 – how many runs a player is above/below average in 150 games on offense. The y axis is at bats – how many at-bats that player is expected to have. Not all of those at-bats are projected at the major league level, obviously – some of them will occur in the minor leagues.
The light red line indicates the cutoff for average. The dark red line indicates the cutoff for replacement (commonly around -18 to -20; I used -20 for the purposes of this graph).
The purple line? That represents the playing-time cutoff. In the past 10 years, MLB has averaged roughly 166,000-167,000 at bats a season. And so the purple line is the point at which projected playing time for players of that caliber meets or exceeds the number of available at-bats.
At the far right of the curve, there is no competition for playing time – all of those guys are going to find at-bats. As you start to move left, competition increases. And by the time you get to the replacement-level players, what you discover is that you have enough players to cover a full third of the at-bats in all of MLB, and that you really don’t need that many. Essentially by definition half of the at-bats in MLB are being used by players who are average or above, right?
Once you get down to the replacement level, you’re dealing with a lot of available players for very few availabe at-bats – the vast majority of ABs have been taken already by better players. There’s very little reason for a team to keep around a guy who’s below replacement, because the competition for playing time at that level of play is so severe.
And this is why the marginal value of a replacement player is zero – he isn’t any more valuable than a dozen other players who are rotting away in bus leagues, he’s just more fortunate. In measuring a player’s value, the question (at least as far as I’m concerned) is, “How many games would a team win without this player, as opposed to with him?” If one of our replacement-level players gets injured, how many fewer games would team win?
And the answer is zero, because there’s another guy out there just like him who the team can get to replace him.
(As an aside – the graph would continue to rise on the left-hand side if Rally included guys in A ball and the rookie leagues. You could go further, adding in college teams, high school teams, your beer league – the population of pro baseball players is really just the rightmost edge of the population curve of all able-bodied people.)