Dahl didn't get into center field until the sixth inning, but he nearly immediately made two outstanding throws that lit up the scoreboard. First, he hit 95.6 mph on a throw from center to home trying to catch Eloy Jimenez on Josh Naylor's single. While Dahl wasn't able to get Jimenez, that was quickly forgotten, because on the next play, he got up to 96.7 mph throwing out Naylor at the plate on a Carlos Asuaje hit.
While that's obviously a sample size of only two throws, it's consistent with the scouting reports, and obviously you can't fake throwing that hard. When we look at the Major League average for "competitive throws" (which we've defined as the average of throws above a player's demonstrated 90th-percentile arm strength, to eliminate the easy lobs back in), it's 89.1 mph, which should show you what 96.7 mph means. In terms of raw strength, there have only been 152 throws at or above 96 mph by Major League outfielders combined this year, and only 25 have managed to do it more than once. Dahl very nearly did so in his first tracked inning.
Remember, also, that a strong arm should be especially beneficial in the vast expanse that is the Coors Field outfield. As of earlier this month, Rockies outfielders were playing deeper than average across the board. In left, where Dahl may start off as the injured Gerardo Parra heals, that was an average of 300.8 feet, the fifth deepest, fewer than five feet shallower than the D-backs and more than 21 feet deeper than the shallowest group in Houston, due to obvious ballpark differences. In center, their average of 322.5 feet was tied for fifth deepest; in right, the average of 299.8 feet was second deepest.
The only team routinely playing deeper was Arizona, and that makes sense -- the D-backs not only have a large outfield but a slew of infielders and emergency fill-ins trying to patch over holes caused by injuries. The math here is simple, really. In a park where the ball flies farther and the fences are deeper, it makes plenty of sense to be farther away from home plate. It also leaves you more distance to cover when getting the ball back in.
The Rockies already employ one of baseball's strongest outfield throwing arms, anyway. While it's natural to wonder if Dahl's promotion is timed in part because a trade of Charlie Blackmon or Carlos Gonzalez might be coming shortly, for now they're all wearing purple and black, and look where Gonzalez ranks on our latest list of top outfield arms:
2016 top outfield throwing arms, through July 24, minimum 30 throws
1. Aaron Hicks: 100.5 mph
2. Starling Marte: 96.7 mph
3. Gonzalez and Carlos Gomez: 95.9 mph
5. Jackie Bradley Jr. and Jake Marisnick: 95.5 mph
Parra also ranked in the top 20 at 93 mph, while Blackmon, at 89.4 mph, came in at just about average -- and just about exactly at his 89.8-mph average from last year.
So when Dahl makes his Colorado debut, remember that it's not just about the bat. It's about the arm, too, in a park that might require one nearly as much as anywhere else. After all, the trick in Coors Field isn't really scoring runs. It's preventing them, any way you can.