How do good teams construct their rosters? It’s a question that fans, sports analysts, and general managers have grappled with for years, and will in all certainty continue to grapple with going forward. With the abundance of time that exists due to the lack of baseball games being played, I figured now would be a good time to dive into how the 2019 teams constructed their roster, and see what trends, if any, were shared among good teams.
To do this, I recorded for all the teams in the American League the WAR values of each method of player acquisition: Amateur Draft, International Amateur Free Agency, Free Agency, the Rule V Draft, Major League trade acquisitions and minor league trade acquisitions. Then, I divided these WAR values by the total WAR value of each team, to determine what percentage of that team’s production came via that method of acquisition. Finally, I graphed each by the number of games each team won, to see what relationship, if any, existed between them.
The resulting seven graphs produced results that were at best mixed, at worst, inconclusive: in fact, no graph had a R-squared value less than 0.268. Even so, a glance at a few of our graphs does show a few interesting trends.
It might seem a paradox that worse teams generally see a larger percentage of their performance come from drafted players than better teams. However, a comparison with a graph of the total WAR values from drafted players sheds a little bit of light on the situation.
Although receiving less WAR total from drafted players, bad teams see a larger percentage of their total WAR come from them precisely because they’re bad teams. They won’t be shopping at the top of the free agent market or competing for contributors at the trade deadline to supplement their drafted players, which would drive that percentage down.
The other graph that I want to showcase is the one that has the strongest correlation, that of players acquired via trade as minor leaguers. These were defined as players who were traded before making their Major League debuts (thus, players that received a cup of coffee were counted as “Major Leaguers” for this exercise).
More than any other graph, this one reflected the reality of the league, with the 96-win Rays and the 97-win Athletics — both small-market teams that rely on lots of trades — outperforming all other teams. Two teams saw negative production from this group: the Detroit Tigers and the Baltimore Orioles, two teams that have been tanking. Even so, this graph does not show the whole picture, as the White Sox, Red Sox, Blue Jays, and Indians also saw roughly the same percentage of performance from this group, despite winning 72, 84, 67, and 93 games, respectively.
Ultimately, there is no one way to make a winning roster, and this study does nothing to dispute that. Every general manager has their own set of circumstances to contend with, from inherited roster construction to budgetary restraints and ownership mandates, that forces them to find their own way to put together a winning roster.