How good should a team want their depth to be?

The last few years, the Yankees have regularly filled their lineup with some of the top players at their particular position — with the possible exception of Gary Sánchez, in fact, one could even make the case that every member of the Yankees’ starting lineup is, at worst, top-15 at their position. Quite a few have strong cases to be within the top five. Unfortunately, however, many of those players have not filled the lineup on a regular basis, as the Yankees have been forced to dive deep into their depth due to repeated injuries.

The regular use of backups in the past few seasons has gotten me thinking about what the baseline for backups ought to be for a team right in the middle of their window of contention, such as the Yankees. Obviously, in an ideal world, you want your depth to perform just as well as your starters, but that’s not realistic. Still, for a team with a star-studded lineup, would simply having backups who could sub in at a league-average level for their position be adequate?

To test this, I drew on the FanGraphs Depth Chart projections, taking the 30 players projected to play the most games at each position. This involved a little bit of manual adjustment in order to account for positional changes when players switched teams and for players listed at multiple positions. Ultimately, I tried to arrive at a baseline for what, hypothetically, the average starter at a position is projected to produce. (Note: due to the fluid nature of the positions, both right field and left field were combined into corner outfield; designated hitter was omitted due to extensive overlap with other positions in the projections)

Now, obviously projections err on the side of caution and tend to underestimate a player’s performance, but even so, my initial reaction was, honestly, surprise at these results. Seven of the ten Yankees with more than 110 plate appearances last year exceeded these projections in respect to OPS, with only Sánchez (.618, compared to .726), Brett Gardner (.747 to .798), and Mike Tauchman (.648 to .798); this doesn’t even include Giancarlo Stanton either, who posted a .887 OPS in 94 plate appearances.

How good would this middling team be? This average lineup combines to 17.2 WAR, or about 2.15 per player. To put that in perspective, in the last complete season, the Yankees starters put up more than 25 WAR and averaged more than three wins per player. While a team of all average starters would not be running away with a division title, they would nonetheless put up a respectable performance.

For depth pieces and injury replacements, putting up a respectable performance would be more than adequate for the Yankees deep lineup. Time will only tell, however, whether the Yankees’ depth pieces will be able to maintain that standard over the 2021 season. They were up to the task in the Next Man Up year of 2019, and faltered during the shortened 2020 campaign. Hopefully, the Yankees can count on both better depth this year, along with better health from their starters.