Julio harnessing arm strength, accuracy in outfield

This story was excerpted from Daniel Kramer’s Mariners Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

WASHINGTON -- As optional pregame work was underway on an extremely muggy evening in Baltimore last week, Julio Rodríguez snuck up behind Perry Hill and told the Mariners’ infield coach that he wanted in on the action.

Rodríguez had just gone through his own extensive throwing program with first-base coach Eric Young Jr., who oversees Seattle’s outfield defense, but still had enough juice to fire a few more at shortstop.

And he didn’t miss a step, corralling every grounder hit to him and unleashing clean heaves to all the bases.

No, Rodríguez isn’t toying with an infield shift like Fernando Tatis Jr. But he did joke that he could play third base if needed, when Colt Emerson missed three games with a back spasm -- or even twirl an inning of relief for Seattle’s banged-up bullpen.

Rodríguez has certainly shown the arm for each throughout this season, and no moment encapsulated this more than his 96.2 mph heave that ignited a double play in last Monday's tense win over the Orioles.

“It's really just rearing back and chucking,” Young said. “But all the pregame work, all the drills we do, and like I said, our throwing program that he does, all those things become second nature. And they showed up perfectly in that moment.”

It’s not outlandish for an outfielder to reach that velocity, but we rarely see it with such accuracy.

Rodríguez corralled the liner 381 feet from home plate, just in front of the warning track and delivered a no-hop dime to Ryan Bliss, who made the quick tag. It was tied for the Mariners’ fifth-hardest outfield assist since Statcast began tracking the metric in 2015.

“The biggest thing is kind of getting onto the ball,” Rodríguez said, “because at that point, when it's like a deep fly ball, my mentality is that the runner is always tagging. So I try to always go back as fast as I can to be able to get at least a good enough gauge between myself with the ball to be able to have some kind of momentum forward. And then try to make a good strong throw to the base.”

That highlight tied into a broader effort of Rodríguez’s extensive work behind the scenes -- even on extremely humid days before the ballpark's gates open.

He’s always had the cannon, having averaged 92.4 mph on the top 10% of his hardest throws since his rookie year. That number is tied for 19th highest among 224 outfielders with at least 50 such tracked throws. He’s also topped out at 100.6 mph, and overall, ranks in Statcast’s 89th percentile in arm value.

But harnessing its accuracy is the next step, and it’s showed by how many outfield assists he has already.

Rodríguez has four this season -- two shy of his 2025 total, matching his 2024 total and more than 2023 and 2022, when he had three apiece.

“It's so important to have a clean throwing program,” Rodríguez said. “The focus is always on the throwing program and to try to have that accurate throwing program -- always kind of hitting the chest, making sure the ball flies well, things like that. That's how you practice your accuracy.”

The throwing program with Young is fairly simplistic. Rodríguez starts with light catch along the foul line then creates a slow distance between each heave until he’s way out in deep center field. And each throw to Young is deliberate.

“It's a daily thing,” Rodríguez said. “Every time I'm on the field, like playing catch, I always have that mentality of making sure I use my feet well, have good extension, making sure my body reaches the target.”

When he goes to a new ballpark, Rodríguez typically spends the first day of the series scouting dimensions. This is more during batting practice, when he shags fly balls and throws to the infield.

“Depending on the field, maybe sometimes you have a bigger outfield that sometimes you've got to know when to actually throw or what balls you can get to and when you have to hit the cutoff,” Rodríguez said.

As for the arm strength conditioning, it’s more maintenance once the season begins, with plyometric balls and exercises from Seattle’s athletic training staff.

“That's something I try to do a lot, too,” Rodríguez said.

Young says he’s noticed that some teams have more trepidation to run on Rodríguez this year. Others, though, continue to push the envelope. Regardless, he’s established a reputation that all teams must account for.

“I feel like they know that I'm a very capable outfielder out there,” Rodríguez said. “And I think they've got to be a little smart. I feel like people have got to pick their chances.”