SEATTLE -- A Mariners team that has started six different first basemen on Opening Day over the past six seasons will have a seventh next season. But if things go to plan, that merry-go-round is about to stop with Evan White.

The promising 23-year-old prospect, who has never taken a big league at-bat, officially signed off on a guaranteed six-year, $24 million deal on Monday that could keep him in Seattle for up to nine years before hitting free agency.

And while White hasn’t been handed the starting job at first base just yet, there’s no doubt the defensive standout is the long-term answer at that position and a strong likelihood now to be on the field when the Mariners open their 2020 season against the Rangers on March 26 at T-Mobile Park.

“I would say going into Spring Training, he’s going to get every opportunity to be the first baseman when we break camp,” general manager Jerry Dipoto said Monday at a press conference announcing White’s deal. “As I said to him through the course of this, he’ll get a very long rope. Because we believe in the player, we believe in his skill set.

“We’ve all done this enough to know it takes time. You need at-bats and time to get comfortable at this level, but it doesn’t take as much time as you think. When you throw the best young players in the deep end of the pool, they learn how to swim pretty quickly.”

Jay Bruce opened the season at first base last year, but was later traded to the Phillies. Previous Opening Day first base starters since 2014 were Justin Smoak, Logan Morrison, Adam Lind, Danny Valencia and Ryon Healy.

In White, the Mariners believe they have a player and person who should be part of their future foundation. The club began talking about a long-term offer for him internally last August, broached the subject to his agent at the recent General Managers Meetings and made a formal offer to White last week.

By Wednesday, an agreement was in place, and the deal was finalized on Monday after White passed a physical exam in Seattle. At a minimum, he’ll earn $24 million over the next six seasons during the time he’d normally take home the MLB minimum of about $550,000 for three years and then go to salary arbitration for three years.

The risk, for White, is that the Mariners now have team options for the first three years of what would have been the start of his free agency -- from 2026-28 -- that will total an additional $31 million if all three are exercised.

“It’s a fair deal for both sides,” Dipoto said. “We’re sharing equally in the risk and potentially in the upside, Evan on the front end and us on the back.”

White said he weighed the pros and cons of the deal carefully and decided the long-term security was the best thing for him and his family.

“The first time I set foot in Seattle was in 2017 when I got drafted. I really fell in love with the city, the people and the ballpark,” he said. “Right away I knew this is where I wanted to be, so I’m very thankful for this opportunity and excited to get to work.”

White’s unusual long-term deal -- just the fourth in Major League history for a player who has yet to play a big league game -- sends a sharp signal about where the Mariners believe they’re heading and the kind of players they want at the heart of that movement.

“This is a way to start laying a foundation and creating a stable base for this roster,” Dipoto said. “Choosing Evan as the guy we wanted to be at the center of it, I really can’t say enough about the person we’re dealing with here.”

Dipoto has churned the Mariners’ roster at a dizzying pace since coming to Seattle in 2016. But the hope now is that White and other promising prospects like Kyle Lewis, Shed Long, J.P. Crawford, Jared Kelenic, Julio Rodriguez, Logan Gilbert, Justin Dunn and Justus Sheffield will provide a core that fans can grow with as well.

“We know for the club, there is some risk in deals like this,” Dipoto said. “That will not stop us from venturing out and doing it again if we get the opportunity because we want this young group to stay together. And we want our fanbase to be able to recognize and associate with a team that is familiar to them, where there are players that the fans want to see day-in and day-out that they watched grow up.

“Ken Griffey Jr. said something to me when we were at Cooperstown [for his Hall of Fame induction in 2016] and it was that no team ever treats you like your first team and he’d never forget what it felt like to come through and make his debut at that time with the Mariners,” said Dipoto. “That’s what we want this group to feel like and we want our fanbase and community to feel that way about this young team. And I think this is the first day where that [starts to be] a reality.”