At Sports Info Solutions, we developed the PART system to better analyze the different components of defensive play in MLB. PART, which stands for Positioning, Air Balls, Range and (Infield) Throwing, has allowed us to best assess how much of a fielder’s defensive performance is based on his positioning (which is assessed to his team) as compared to his skill (for which the player is credited or debited). 

Now, we’re able to take that and utilize it in the minor leagues.

At the SABR Analytics Conference last weekend, our research analyst Sarah Thompson did a presentation titled “Evaluation of Minor League Defense Using Detailed Contextual Data.” She walked through how we’ve applied our methodology to players across different levels.

One of the cool things to come out of this work was an all-inclusive look at how outfielders fare against different levels of play difficulty. Below is a chart that compares minor league and major league out rates across different expected out rate groups.

As the degree of difficulty of the play increases, so does the gap between the minor league and major league out rates.

To hone in more specifically on what kinds of plays make up those disparate groups, take a look at the following chart.

Those outfielders who can make catches of this nature in the minor leagues, like Michael Harris II of the Braves, generally have their skills translate well to the majors. Harris averaged 10 Runs Saved specific to Range & Positioning per 1,000 innings in the minors and then was credited with 6 PART Runs Saved in 1,021 innings this past season with the Braves.

There are some outfielders whose minor league numbers may not look as good but who are able to live up to their potential once they reach the major leagues. Cristian Pache of the Athletics averaged -8 PART Runs Saved per 1,000 innings in the minor leagues but then had a PART Runs Saved of 9 per 1,000 innings in his brief stint with the Athletics.

Pache fared better at the tougher plays after his ascension.

On plays with an estimated out rate between 56 and 65%, Pache caught only 3 of 11 of those in the minors in 2021. But at the major league level, he caught 8 of 9 of those plays. That alone explains a decent chunk of that gap between the levels.

As SIS continues to innovate and further develop its minor league defensive evaluation tools, we’ll try to provide more data and context in the future. Our biggest takeaway from this subject: You have to be pretty good to be playing outfield in the major leagues.