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.

SEATTLE -- Luis Castillo’s brief two months with the Mariners have been perhaps a microcosm of where Seattle’s front office stands and how far it has come from when it embarked on a massive roster overhaul beginning in 2019.

When the Mariners acquired Castillo at the Trade Deadline, they didn’t just bring in a top-end pitcher for a playoff push. They also showed him a positive clubhouse culture, supplemental pieces that could lead to sustained winning beyond 2022 and a $108 million offer in line with what would’ve been market value in free agency. For all those reasons, Castillo went all-in by committing his prime years to Seattle.

“I think this is what we dreamed up when we went through the initial stage of [the rebuild],” Jerry Dipoto, the Mariners' president of baseball operations said. “It was to build a young strong foundation from which to grow and then to go out and acquire impact players who could come in here and take us to that next level. And I think it's happening. It's happening for us right now. It's going to continue to happen for us.”

With the backing of Mariners chairman and managing general partner John Stanton, Dipoto and assistant GM Justin Hollander always said that the Mariners would spend when the time was right, and it’s been a watershed year in that regard.

That spending has also been on talent that the club has acquired and cultivated, with Robbie Ray’s free-agent deal last offseason the only one among players that weren’t already under club control. Castillo joined Julio Rodríguez, J.P. Crawford and Andrés Muñoz among players receiving long-term extensions over the past 12 months, and Marco Gonzales also fits this bill on a deal he signed in 2020.

“It's incredibly gratifying to know that we have the backing of ownership as we got to this point,” Dipoto said. “We were able to reach deals with Luis, with Robbie Ray, with Julio, with J.P. to keep that talent here in Seattle and continue to add rather than just sitting back and watching what we've done because we haven't done anything yet. All we've done is created a pool of talent to move forward with.”

Dipoto called these deals “landmark events” in the scope of Seattle’s long-term roster trajectory, and it wouldn’t be shocking to see the front office attempt to lock up more homegrown talent. Here’s a look at other extension candidates on the active roster, listed in the order in which they’re eligible for free agency:

RF Mitch Haniger
Free agent: 2023
At this point, any extension would probably only come in the form of a qualifying offer this offseason, given how close Haniger is to free agency. The QO is worth the mean salary of MLB's 125 highest-paid players and will likely be near $19 million for next season, more than Haniger’s total earnings over his six-year career. Given the uncertainty of Seattle’s outfield with Kyle Lewis’ long-term health and the struggles of Jarred Kelenic and Jesse Winker this season, bringing back the veteran on a shorter-yet-pricier deal that would allow him to re-establish his value (and health) might make sense for both sides.

1B Ty France
Free agent: 2026
Seattle’s analytics staff loved France well before it acquired him in a 2020 trade that Dipoto has referred to as one of the most significant moments in the rebuild. With an everyday gig, France blossomed into an All-Star this year while playing above-average defense. He’s also had a team-first attitude, most notably by shifting to third base with Eugenio Suárez sidelined, and he’s taken on more of a leadership role. France, who is a contact-over-power hitter, also wouldn’t cost as much as Matt Olson ($168 million), Freddie Freeman ($160 million) or Paul Goldschmidt ($130 million).

SP Logan Gilbert
Free agent: 2028
The towering righty has been a workhorse in his first full MLB season, leading the league with 31 starts and the team with 177 2/3 innings. He’s had a few bumps this year as he navigates the rigors of the six-month stretch for the first time, but he’s also shown stretches of complete dominance, winning AL Pitcher of the Month honors in April. Starting pitchers with a five-pitch mix, elite velocity -- and above all, acumen -- don’t grow on trees, and the 24-year-old has already shown big upside for the long term.

C Cal Raleigh
Free agent: 2028
Despite what Raleigh showed in the Minors, even he didn’t envision that he’d lead all MLB catchers with a whopping 25 homers this year. Not only that, but Raleigh has also been a vital bat for the Mariners this year, ranking third on the team behind only Rodríguez and Suárez with 4.0 wins above replacement, per FanGraphs. For a position that has taken such a huge collective dip in offensive production this decade, Raleigh has shined while also taking on a more pronounced role overseeing a diverse pitching staff.

SP George Kirby
Free agent: 2029
Like Gilbert, Kirby has already wowed in a small career sample, with an ability to throw strikes, install new pitches and shine against some of the most daunting opponents. He’s just 24 years old but has already shown that he belongs and despite his rookie status, he will be a huge part of the Mariners’ postseason plans if they clinch during this final homestand. He’s the type of young pitcher that organizations build around.