A Brief Tangent on Arm Strength

Arianna Grainey-Imagn Images

Ceddanne Rafaela has a weak arm. He also has a strong arm.

This is an analysis I’ve wanted to do for a while. It’s not that important or complicated, and most of it is fairly obvious. But it gets at something that comes up from time to time in the various places baseball is discussed online. The conversation tends to start like this: Team A should sign Player X and move him to a new position. Inevitably, one of the first questions asked about such a plan is whether Player X has the arm strength to play that new position.

The number that gets cited to “yay” or “nay” such a follow-up is arm strength, in miles per hour. But ask any baseball fan to sit with this for a moment, and they’ll raise a concern. Arm strength, to some degree, is a function of position. A third baseman has a longer throw to make than a second baseman. A right fielder has a longer throw to make than a left fielder. This means players with better arms tend to play those positions, as we can see in this plot:

It also means the official arm strength figures reported by Baseball Savant aren’t quite transferable between positions. We can’t say whether Player X has the arm strength for a given position if he’s never played there before.

That brings us to Rafaela. Most fans think of him as the next-best center fielder in the majors after Pete Crow-Armstrong. But Rafaela also happened to play 24 games at second base last year. His published arm strength at second base in 2025 was 78.5 mph. In center field, however, his published arm strength was 93.4 mph. Since 2021, that’s the largest gap for a fielder between two positions (excluding first base):

Looking at the plot, if we assumed Rafaela’s published arm strength at second base would be his arm strength in center field, he would have one of the three weakest arms in center last year. Instead, he wound up having one of the strongest. That’s because this is the type of throw that gets an out at second base:



While this is generally what it takes to get an out from center field:

It’s worth noting the methodology behind the arm strength figures you see on Baseball Savant. Basically, it’s the average of a player’s strongest throws. From the Baseball Savant arm strength leaderboard:

Since the demands of each position grouping are different, the averages and qualifiers are different as well.
– 1B: average of top 1% of throws (minimum 100 throws to qualify);
– 2B/SS/3B: average of top 5% of throws (minimum 75 throws to qualify);
– OF: average of top 10% of throws (minimum 50 throws to qualify)

So, how much arm strength might we expect a player to gain or lose with a position change? I found all of the players with the minimum number of throws at multiple positions in a season since 2021. I then took their arm strength at each position and averaged the differences. It’s about what you’d expect. Players throw harder when they’re in right field than they do at first base: 


Arm Strength Change

Pos	Gain/Loss (mph)
RF	+1.5
3B	+1.1
SS	+0.8
CF	+0.3
LF	+0.3
2B	-2.0
1B	-4.8

Source: Baseball Savant

Fielders qualified at multiple positions in a season

While performing this analysis, I found that Tom Tango had done a more comprehensive piece on these positional equivalencies, looking specifically at players who moved between any two positions. Using his method gives us this nice grid:

For instance, a fielder moving from second base to center field adds about 6.5 mph on average to their arm strength figure. Rafaela gained nearly double that, going from a roughly average throwing second baseman to one of the hardest throwing outfielders in the league. But how much is all that arm strength worth?

In terms of value, arm strength is the lesser of the fielding skills compared to range. There are simply fewer opportunities to make use of a strong arm. Baseball Savant only publishes arm value components for outfielders, where arm and range are easier to separate than they are for infielders. Arm value is derived through a series of estimates and rates, comparing how often a baserunner should attempt to advance on a fielder with how often they actually do (and how often they do so safely). This is done using a distance-time model, which considers the speed of the runner, the arm of the fielder, and the distance each are from their target.

In other words, arm value isn’t just about pure strength. Preventing runners from advancing requires a variety of other skills, like getting to the ball, fielding it cleanly, and making an accurate throw. And even a great throw is dependent on another fielder receiving the ball and applying the tag. Plus, a runner’s decision to advance is partially based on the game state and other nuances specific to a play. There are many reasons a strong arm doesn’t always equal a valuable arm, and vice versa.

This also means that each outfield position has a different baseline arm value:

Arm Value by Position (Per 100 Throws)

Value	LF	CF	RF
Advance	-2.26	-1.62	-2.52
Hold	+1.14	+1.29	+1.52
Out	+0.87	+0.52	+0.91
Total	-0.25	+0.19	-0.09

Source: Baseball Savant

Arm strength seems to be most impactful for right fielders. That’s interesting, though it’s also fairly intuitive. Right fielders are often asked to make very long throws, and can get dinged for allowing runners to advance. Those with strong arms are both more likely to throw runners out and to convince runners to stay in place.

I also wonder if there’s a reputation advantage. Balls hit to left field, for instance, allow the runner to read and react to the play in front of them, while balls hit to right field force the runner to refer to the scouting report. I’m sure many runners feel uneasy when they can’t see Addison Barger:

Center field arm value is the least responsive to arm strength. There’s just not a lot even the strongest arm can do from 400 feet away. A center fielder with a valuable arm is a center fielder who takes a good route to the ball and cuts it off clean, rather than one who racks up assists.

Rafaela happens to have all these skills. He has both tremendous range and a strong arm. He finished 2025 with two runs above average from his arm, seventh among center fielders and in the top 15% among outfielders. That’s not a lot, but hey, it isn’t bad for a soft-tossing second baseman.

Source

* This article was originally published here