As trade rumors swirled, Julio Rodriguez urged Mariners to keep Bryce Miller and Bryan Woo

PEORIA, Ariz. – From his vantage point in center field, Julio Rodriguez had more insight than most into what made Mariners’ pitchers so good last season.

Rodriguez was particularly impressed with how rookies Bryce Miller and Bryan Woo acquitted themselves after they jumped straight from Double-A to the majors, quickly establishing themselves as legitimate big-league arms in Seattle’s rotation.

So impressed was Rodriguez that, as the offseason unfolded and trade rumors swirled about Miller and Woo potentially being shopped, the star center fielder made his feelings known whenever he’d check in with Mariners front-office executives. Do not trade them, he’d say.

“Oh, definitely,” Rodriguez said Friday. “They’ve learned so much already, and I feel like what we saw last year was their base. They worked through a lot of things. Not everything was pretty and shiny for them all the time. They had to adjust and they had to work, and it was really nice to see from guys who were really young and just coming up.”

Rodriguez views Miller and Woo as core pieces for the future of the organization.

“I mean, they’re electric,” he said. “They have different pitches, but they’re similar in a lot of ways. They can blow it by anybody. … I definitely see myself playing with them for a long time. We’re all young and we all knew each other coming up the system, and it feels really good to have the same core players. You know what you’re going to get from them. They are who they are, and they’re really good people to have on your team.”

A number of teams, knowing the Mariners needed to upgrade their lineup, inquired about their young pitchers this offseason.

The Twins had initially asked for Miller in exchange for veteran second baseman Jorge Polanco. The Mariners balked and eventually finalized a trade that didn’t include Miller (sending four players to the Twins instead: reliever Justin Topa, starter Anthony DeSclafani and prospects Gabriel Gonzalez and Darren Bowen).

Jerry Dipoto, president of baseball operations, said early in the offseason that the Mariners weren’t inclined to trade either Miller or Woo, and industry sources said the Mariners put a high valuation on their two young starters in talks with other teams. No one came particularly close to matching the asking price.

Which was a relief to pitching coach Pete Woodworth.

“Obviously, I’m extremely glad they’re still here,” Woodworth said. “We know who they are, and we know what they can do, and we know what they need to improve on.”

Miller and Woo relied heavily on their fastballs last season; Miller threw his four-seam and sinkers 66.1% of the time, and Woo threw them a combined 72.5% of the time.

Woodworth said their fastballs will still be the foundation of their arsenal – because they’re effective – but the main objective for both pitchers this offseason was to improve their secondary offerings.

In that regard, they’re following a similar blueprint Logan Gilbert and George Kirby used the past couple of years to round out their arsenal.

Miller, 25, learned to throw a splitter this winter – the same pitch Gilbert and Kirby began using last season.

On Thursday, Miller threw 30 pitches in live batting practices – facing veteran hitters Mitch Haniger, Ty France and Polanco – and sat 95-97 mph with his fastballs. He also mixed in five splitters, though he said afterward that it’ll take more time and more tinkering for him to have better command with the new pitch.

The 24-year-old Woo didn’t add any new pitches to his mixture, instead working on refining his slider and cutter.

The early returns in camp have been encouraging for both.

“They’re just scratching the surface,” Woodworth said. “… And when you put it all together, like what happened with Logan and what happened with George, once the secondaries start becoming more solidified in the arsenal, it becomes really fun.”

Strong first impression for Vargas

Woodworth certainly had fun watching Carlos Vargas’ first live batting practice Friday afternoon.

Vargas, a 24-year-old right-handed reliever acquired from the Diamondbacks in the Eugenio Suarez trade early in the offseason, retired all four batters he faced on about 20 pitches.

He got Mitch Garver and Ty France to ground out, then struck out Dominic Canzone and Rodriguez on sliders.

“Really good,” Woodworth said.

Vargas has a reputation as a pitcher with erratic command; he pitched 4⅔ innings for the Diamondbacks last season, walking four batters, hitting another and striking out seven. In 90 minor-league appearances, he has 185 strikeouts and 97 walks in 118⅔ innings.

Vargas throws three pitches – a sinker, a cutter and a slider – and the Mariners have had a simple message for him this spring: Just throw it down the middle of the plate.

“It’s a little wild at times,” Woodworth said, “but his stuff is real.”