With no minor league season in 2020, the pandemic has provided a unique opportunity to examine philosophical differences in team prospect development strategies. This article examines team differences in prospect promotion aggressiveness between 2019 and 2021.

In a normal season, prospect promotions are based on a somewhat messy combination of performance, age, development, team need, and service time manipulation. With no minor league season in 2020, comparing initial minor league prospect placements in 2021 to their minor league placements in 2019 provides a cleaner look at differences in team prospect development strategies–with placements only capturing development and age (and service time manipulation in a few cases), rather than team need and performance. As will become clear by the pervasiveness of promotions, prospect development did not cease just because minor league baseball did–players continued to practice and grow, whether at the alternate site or elsewhere, with many lower ranked prospects organizing their own training independently. While the unique pandemic circumstances are a relevant consideration when analyzing the development of particular players, there is no particularly compelling reason they would have impacted team development philosophies very differently–all organizations experienced the same pandemic, after all.

The table below shows each team’s average promotion aggressiveness in 2021. To calculate this score, I assigned values based on each prospect’s highest level reached in 2019 and their starting level in 2021: a six for MLB, five for Triple-A, four for Double-A, three for High-A, two for Low-A, one for Short-Season A, and zero for Rookie. I then subtracted highest 2019 level from 2021 starting level for each prospect, and calculated the average score for each team. For instance, Bobby Witt Jr. was assigned a zero for 2019, as he peaked in the rookie-level AZL, and a four for starting in Double-A 2021–his promotion score was thus a four. Players with MLB as their highest level in 2019 were excluded, as most of these guys are established major leaguers whom have completed their prospect development. Three variations of the score are shown: one including all prospects, one excluding prospects who peaked in rookie ball in 2019; and one excluding both 2019 rookie ball prospects and prospects who peaked in Triple-A in 2019. It was convenient, but overly blunt to group all rookie leagues together, so the second variation is shown. The third variation excludes prospects who peaked in Triple-A in 2019 as these prospects are most likely to be impacted by service time manipulation, and also they are mostly done with their development–a majority tend to repeat the level. The table below shows the Pirates to be among the most aggressive teams across measures, promoting their prospects an average of 1.37 levels in 2021 over 2019. Atlanta, on the other hand, is among the slowest teams to promote their prospects, with an average promotion of .44 levels.

The average team promoted their prospects .98 levels including the full sample, .67 levels excluding 2019 rookie leaguers, and .90 levels excluding 2019 rookie leaguers and Triple-A-ers. Prospect placement decisions should be considered in light of each team’s developmental philosophy. For instance, Seattle conservatively started Julio Rodriguez in High-A this year–the same level he crushed with a 200+ wRC+ 2 years ago at 18 years old. He has since held his own in much harder leagues, including the Arizona Fall League and the Dominican Winter League. Without considering team philosophy, an analyst might be concerned about the conservative placement (I’m projecting here, smarter folks than me have generally not been concerned). Do the Mariners not think the super young super stud has developed much since 2019, even though he is at a prime age for development? No! Their conservative decision is less concerning once their more passive team development philosophy (.41 promotion aggressiveness score for the full sample, the lowest of any team) is accounted for (not to mention the Mariners have not hid their affection for J-Rod). The same logic holds for the Dodgers conservative placement of Miguel Vargas–he is repeating High-A two years later, but the Dodgers have been one of the slowest teams to promote their non-rookie league prospects. On the other hand, the Royals’ development philosophy is more aggressive than the average team–but Bobby Witt Jr.’s four level jump is still much larger than the average promotion for Royals prospects–an exciting sign of their enthusiasm for his development.

In sum, when considering prospect development, it is better not to ignore philosophical differences in team strategies.