Midseason Trades, in Retrospect

One of the key cogs in the 2019’s final months for the now-champion Washington Nationals was Asdrubal Cabrera. Cabrera didn’t have a fantastic postseason, statistically speaking, but he did have some impactful hits and was a huge part of the Nationals late regular season effort offensively. He provided a switch hitting bat, he walked more than he struck out, his OPS+ was a robust 143. 

The title of this post and the subject of it’s first paragraph are in contradiction though. Cabrera was not in fact traded midseason, but released. Still, he was picked up near immediately by a team rounding into form and in need of depth. Cabrera made a case for himself to be more than depth all the way to playing in each of this seasons seven World Series contests. 

Cabrera is one of a small group of position players every year who play a not unsubstantial amount of time with more than one team due to a trade, release, or otherwise. What follows is a brief look at how those traveling position players have performed in recent years. Obviously, the case of Cabrera is the most recent, and most positive, outcome a club could hope to achieve. For the group at large though, the picture is a decidedly mixed bag. 

First, a bit about these players. To qualify for this group, a players must: be a position player, play for two teams in a season, receive at least 100 PA’s for either team, and have a qualifying season overall (502+ PA’s cumulatively). Dating back 5 seasons, 38 players (and 39 player-seasons, as Cabrera actually qualifies twice) appear in this exercise. 

It should be noted that this is obviously a wildly small sample of players, with which partial seasons are then being analyzed; it clearly doesn’t intend to hold water for any meaningful extrapolation.

Unlike in the case of Cabrera, most of these players were traded. To be the sought-after commodity for a midseason trade one might imagine that some selection bias is involved, and they would indeed be correct. On average, this group owned nearly a 110 OPS+ at the time of their team-swaps.

On average, these players nearly performed in line with their prior performance, if only while being subject to slight regression to mean league-wide performance. Their average second-team OPS+ was a bit more than 104. But buyer beware: you don’t make midseason trades for the mean performance of similar situations over the past five years. In reality, these instances have had vastly varying outcomes. Here are those players who moved:

The array of colors alone aim to indicate that teams do not always get what they bargained for in making these sorts of small-sample trades. In general too, one might notice more widespread variations of orange, in this case indicating a dip in offensive production, than maroon. There also appears to be a relatively underrepresented subset of players whose production remained generally unchanged following their move. Of 39 player-seasons, just 10 saw less than 10% offensive change in production in either direction, and 5 of those instances exclusively in 2015.

These next two tables represent the same data, but sorted into leaderboards for risers and fallers following mid-season scenery changes. 

Lo and behold, our protagonist Asdrubal Cabrera has found his way to either end of the spectrum in back-to-back seasons, rising from owning the second largest negative differential following his Mets trade to the second largest following his Rangers release. 

A key point from these two leaderboard though is, again, the presence of regression. The Risers came from a very mediocre group to begin with: their mean OPS+ with their first team was just 99. For the fallers though, their jumping off point mean’t they had farther to fall as their average OPS+ was nearly 123 at the time of their transitions. 

One can certainly look at those fallers and make some ill-advised conjecture in retrospect. We might not generally expect Gerardo Parra to run a 140 OPS+ for a full season, or even a player of  Manny Machado’s caliber to sustain 162. The aging pair of Curtis Granderson and Carlos Beltran might too have been hard pressed to sustain their well above average production. 

Of course, the thoughts of the paragraph above are those of an Armchair GM, with the benefit of hindsight, making conjecture all while working with small numbers. That isn’t the point here. The larger point is that mid-season swaps have not, by and large, resulted in the team on the receiving end getting similar same-year production from the player whom they acquired. 

Not everyone can be 2015 deadline trade Ben Zobrist (-2 OPS+ differential) who sustained his production and then went on to play a key role in the Royals World Series title. That isn’t to forget either those players whose differential was large and positive. Some of those players played themselves into entirely new contracts (looking at you, Yoenis Cespedes).

It also must be noted that teams don’t acquire or pick up players midseason exclusively for their bats. The Nationals were in need of positional depth more than anything, and figured that Cabrera could provide that regardless of an offensive resurgence. 

Regardless of teams’ reasoning, whether it’s making an acquisition to give them an extra edge in a tight playoff race or adding a final piece to better insulate their juggernaut from the random nature of MLB playoff series, it’s tough to predict what exactly they’ll get. As teams bet on a small sample of player production for mid-season reinforcements they are doing just that, betting.