TJ Cotterill

The 2021 third-rounder impressed the organization with his extensive understanding of pitching.

After watching the high schooler take batting practice, the Mariners knew who they wanted with the 12th overall pick.

The 23-year-old righthander was the talk of instructional league and has looked the part in his first pro season.

The 22-year-old righthander did not miss a beat in his first few starts in his return from Tommy John surgery.

The Mariners envision the 23-year-old righthander pitching in the big leagues in 2021, but they are mindful of his workload.

After struggling somewhat against major leaguers at the alternate training site, Marte impressed against less experienced players at instructional league.

The 2020 second-rounder wasted no time impressing his new organization with his multifaceted play and knack for reaching base.

The 20-year-old righthander improved his arsenal in the span of just a few months over the summer.

The Mariners were impressed by what they saw from the 23-year-old outfielder during instructional league.

The Mariners didn’t invite the sidearm reliever to the alternate training site, so he spent his summer working on conditioning and pitch command.

A 40-player instructional league will provide some level of organized development for Mariners prospects.

An epic catch from Kyle Lewis evoked a signature moment from a Hall of Fame Mariners center fielder.

The 2019 fifth-rounder had a breakthrough performance after initially struggling at the alternate training site.

The 21-year-old outfielder focused on working out during quarantine and opened eyes in summer camp.

The 24-year-old righthander began to relax after recording his first big league strikeout last September. He and other prospects will try to lead Seattle back to the postseason.

The 2016 first-rounder’s September play puts him firmly in the discussion for a big league starting job.

White’s long-term contract should hasten his journey to the major leagues, where he will impact the Mariners both on and off the field.

A healthy season resulted in Warren making the Texas League all-star team, which precipitated a September callup.

The Mariners stationed most of their top prospects at Double-A Arkansas in 2019 so they could grow together as a group.

When he made his big league debut, Mariners infield prospect Donnie Walton lived out two dreams at the same time.