Why Spencer Horwitz’s defence at second is worth watching closely

Since Spencer Horwitz established himself as a noteworthy prospect in the Toronto Blue Jays system, significant caveats have been attached to his minor-league success.

Horwitz has raked wherever he’s gone, but his prospect stock has been limited by two primary factors: his relatively advanced age for the levels he’s played at, and his perceived lack of defensive value.

While the first limitation is immutable, it gets less and less relevant the more time he spends in the major leagues. There is a difference between a 22-year-old and a 26-year-old crushing opposition at Triple-A — and the way you’d project future outcomes based on that — but once a player is producing at the MLB level their age isn’t particularly relevant until it comes time to sign an extension or make a trade.

The position issue can be a little trickier. The value a player brings to the table is heavily dependent on the position they play, and how well they play it. In recent seasons much of the discourse around Horwitz has centred around the idea that he could likely hit MLB pitching, but he might not do so enough to make an impact at an offence-first spot like first base.

FanGraphs’ current projections for Horwitz put him somewhere between just below league average with the bat (98 wRC+) to significantly above (116). Taking the average of those numbers (107) you get something that looks a lot like a league-average first baseman in 2024 (105).

Those numbers make it seem like Horwitz looks to be a solid starter at first base, but we are in the midst of a massive offensive downturn at the position. In the last 20 seasons, first basemen have averaged a wRC+ of 110 or better 17 times, and that number has been as high as 120. What we’re seeing in 2024 is the lowest number of the last two decades and the second-lowest is a full three points higher (108).

Generally speaking the bar at first is very high, and doubts about whether Horwitz can clear it are valid — particularly considering he lacks prototypical raw power and has never hit more than 12 home runs in a pro season. It wouldn’t be impossible for the 26-year-old to make it as an everyday first baseman, but even with his advanced approach and contact ability, there would be significant hurdles.

Horwitz hasn’t been a first baseman lately, though. Since the Blue Jays called him up on June 7, 85.9 per cent of his defensive work has come at second base. The 61 innings he’s played there are more than his total from his entire pro career prior to 2024 (59 innings).

It is too early to make definitive judgments on his defensive performance there — for what it’s worth Statcast has credited him with +1 Outs Above Average — but if this is an experiment with any staying power it could be extremely impactful for Horwitz.

If he’s able to become a full-time second baseman, or even log a significant percentage of his time at the keystone, the way Horwitz is perceived and valued will shift significantly.

Compared to first base, the reasonable offensive expectation at second is far lower. In the 20-season sample mentioned above, players at that position have only collectively topped league-average offensive production once (106 wRC+ in 2016).

This season the average second baseman is hitting .242/.304/.363 — a standard that wouldn’t be too hard for Horwitz to beat. Even if he was a poor fielder at the position, he could compensate by standing well above his peers offensively.

A pertinent example of the importance of positional value is the comparison between the careers of Vladimir Guerrero Jr. and Bo Bichette. Both debuted in the same season and have played a comparable number of games. Guerrero (career .836 OPS) has been a better hitter than Bichette overall (.806), but they are in the same ballpark.

Defensively, both players have graded out as below-average at their respective positions by advanced metrics. In Guerrero’s case those numbers are in some dispute based on some of the things he does that are difficult to measure, but for the sake of argument let’s assume they’re approximately correct.

Using FanGraphs’ value calculations, here’s how Guerrero and Bichette compare according to fielding runs and offensive runs (which includes base running) above average.

Based on these numbers, you would assume that Guerrero would have a narrow edge in total value thanks to his gap with the bat, even though Bichette’s glovework has graded out better.

Let’s add a couple of columns to this chart and see what happens:

This is an extreme example because we’re talking about a first baseman against a shortstop, but these numbers are at the core of the attempt to put Horwitz at second base. Positional adjustment numbers are estimates of how difficult certain positions are to play based on data about players who switched spots in the past — and it’s fair to take them with some grain of salt.

The principal behind them is sound, though.

If Horwitz is a first baseman or designated hitter, he takes up one of the spots where it’s easiest for his team to find production and will have to battle to reach a high offensive standard to justify his position. That also means the Blue Jays have to find someone else to play second base, and that player is statistically less likely to produce than a big 1B/DH bat.

If Horwitz plays second, he has an excellent chance to produce far better than the average player at his position, giving his team flexibility to slot big sluggers who lack defensive value into the lineup.

While it’s too early to say whether Horwitz can succeed defensively at second base, it’s clear that it would be both excellent for the Blue Jays and transformative for his career if he manages it.