Last week, I wrote about my favorite award non-frontrunners this season, and there was a mini-discussion in the comments about the sustainability of Trea Turner’s defensive improvements. As we have more years of OAA/FRV, we’re better able to study long-term fielding questions with the data, so I wanted to do a quick look at FRV improvements/declines and see if those changes have held. And since there isn’t quite enough to this topic for me to give this article the full-length treatment — at least not now, while I’m trying to get my playoff predictor utility ready for 2025 — and too long for a comment 10 people will notice, this seemed like a good time for an underutilized InstaGraph©.

I started with every defensive season in which someone played 800 innings at a position in consecutive seasons. I treated corner outfield positions as different positions here, just to keep this as clean and simple as possible. Statcast defense is still a relatively new thing, so we have only 583 two-year runs for individual players. Not enough to break it down further by age or position or component in a meaningful manner, but enough to look at the bottomline numbers. When we look at three-year runs, we drop down to 277 individual players. Thanks 2020!

Of the players who had 800 innings at the same position in three consecutive seasons, here are the 30 largest gainers from the first year to the second. I used FRV/1200 instead of raw FRV.

Nearly two-thirds of the biggest improvers had negative FRV numbers the first season, and averaged a 10.8-run improvement in the second season. While FRV is obviously a volatile number, these players successfully retained a large portion of their one-year gains in the third season, averaging a 6.4-run improvement, with only five players going back into negative territory.

Turner’s 2024-2025 improvement in FRV/1200 is 11.7 runs, which would rank him ninth on this list, and the second-largest improvement among shortstops, behind Tim Anderson from 2017-2018. Turner doesn’t feature here because this is specifically for three-year runs, and the 2026 season hasn’t happened yet. His current Year 1-to-Year 2 gain for 2023-2024 is 4.5 runs — from -8.0 to -3.5 — and therefore not enough to make the top 30. It’s worth noting, though, that ZiPS projects him to be worth about 4.0 FRV/1200 in 2026, meaning he’d maintain about half his improvement from last year to this season.

Now, the decliners:

The story here is similar. The 30 biggest decliners averaged an 11.7-run slide from Year 1 to Year 2. All but two of the 30 were initially in positive territory, and only two players (Trevor Story and Evan Longoria) rebounded to positive territory in Year 3. Compared to the change of -11.7 runs in the first two seasons, Year 3 was still at -7.9 runs below the first year. So again, the biggest declines generally still displayed significant deterioration of their defensive performances.

Despite my sample size misgivings, I also look at the stickiness by age or position. Unfortunately, the results weren’t terribly interesting; the sample sizes were simply too small to draw meaningful conclusions from this part of the exercise.

So, what does this mean? While you shouldn’t take the most recent FRV of a player as some magical this-is-their-true-ability number, large changes in performance are very meaningful going forward. That’s good news for Turner and Phillies fans.