PEORIA, Ariz. -- Taijuan Walker knows what it's going to take. Control the strike zone. Be consistent. Take the next step in the progression from "thrower" to "pitcher." And if it all falls into place, look for the talented 23-year-old right-hander to be one of baseball's breakout players in 2016.
As the Mariners prepare for a season marked by new management and more roster turnover than any other team in the American League, their fortunes may hinge more on their returning young right-hander than any of the newcomers seeking fresh starts in Seattle.
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If Walker can become a dominant force behind veterans Felix Hernandez, Hisashi Iwakuma and Wade Miley, the Mariners' rotation could be imposing.
Walker was a solid starter in his first full season in the rotation last year, going 11-8 with a 4.56 ERA in 29 games before being shut down in the closing weeks to protect his young arm after reaching a career-high 169 2/3 innings.
But there is more there for the 6-foot-4, 235-pounder out of Yucaipa, Calif., who has been ballyhooed as one of baseball's premier young right-handers for the last several years and now appears on the brink of the breakout.
"Absolutely," said first-year manager Scott Servais. "The physical tools are there."
Veteran catcher Chris Iannetta has caught Walker several times already this spring after signing with Seattle in free agency, and the former Angels backstop is among those anticipating a big step forward.

"He looks really good," Iannetta said. "This is a year I would expect him to make a jump. With his ability, he can take the next step forward and be more consistent and be a dominant pitcher."
Walker started last season 1-5 with a 7.33 ERA, 23 walks and 39 strikeouts in his first nine starts. But the light flipped on after that as he went 10-3 with a 3.62 ERA with 118 strikeouts and just 17 walks in his final 20 outings.
"Last year I took a big step toward becoming a pitcher instead of a thrower," Walker said. "I'm still learning. You never stop learning."
It helps to have The King and his vast repertoire of offerings as a role model. Hernandez threw harder, too, when he was younger, but he now relies heavily on a nasty changeup and quality curve to keep hitters off balance.
"The thing with Felix, he still has something in the tank [with his fastball]," Walker said. "But he's a pitcher now. He has that really good curve and changeup that he can throw at any time. That's kind of where I want to get, where I can throw 40 offspeed pitches in a start if I had to and still have a good game."
Such versatility and consistency can be an elusive factor for mere mortals, of course. Walker has had games this spring where his offspeed offerings weren't sharp enough to keep hitters from sitting on his mid-90s heat. He knows what he needs to do to be successful, but executing that game plan against Major League hitters is the ultimate challenge for any young pitcher.
"He's a big strong guy who throws really hard and has great stuff," said Iannetta. "If he commands the ball in the zone, he's going to be successful for a really long time."