Mariners reckon with rare player development failure in Brendan Donovan trade

It's been said once or twice in the past (slight understatement) that the Mariners have had one of the very best farm systems in all of baseball during Jerry Dipoto's tenure in Seattle, with his innate ability to find and develop young talent. As such, when the M's had three first round picks ahead of the 2023 draft, it seemed almost unfair.

Colt Emerson was taken 22nd overall and expectations are sky-high ahead of the 2026 season, ranked as the ninth-best prospect in baseball by MLB Pipeline and expected to make his Major League debut this year. Jonny Farmelo was selected 29th and still needs more time to develop, but he's ranked 78th by MLB Pipeline and offers a fascinating mix of size, strength and athleticism.

As for the Mariners' third first-round pick in 2023, Tai Peete was selected 30th overall (with the final pick of the round). A lot of people can be forgiven for not being familiar with him, but as of this week he has now come to the forefront just by virtue of being the third player the M's parted company with in order to acquire Brendan Donovan from the Cardinals.

Tai Peete a cause for excitement in 2023 draft

At the time of the 2023 draft, Peete was arguably the most exciting of the Mariners' three first-round picks despite being taken after Emerson and Farmelo. In fact, as MLB.com wrote: "Peete might be the most intriguing of Seattle's Draft picks this year, just on upside alone. With a physical build that some scouts have likened to a wide receiver in football, he's still growing."

Helping build up the hype surrounding Peete was that he was one of the youngest players in the draft class at just 17, with reference made to him having as much bat speed as anyone in the prep class. As per his MiLB scouting report at the time there were aspects he needed to work on, such as needing more polish at the plate, but overall the sky seemed to be the limit for the Riverdale, Georgia native.

Ahead of this season, Baseball America had Peete as the Mariners' 10th-ranked prospect, so this understandably begs the question of why they decided to part company with him in order to help acquire Donovan? In many ways, the answer can be found in your perception being your reality.

For example, as good as been the 10th-ranked prospect in the Mariners' organization sounds on a surface level, it does come with the caveat that he had this ranking in a very top-heavy farm system. More so though, even this alludes to the reality that no matter how much potential he does have — and it is plentiful — he has yet to fulfil it to a satisfactory level at this stage of his development.

Mariners decided to take the more sure thing

Baseball America does give Peete plenty of props in mentioning his electric left-handed swing and power, but this is compromised by his lack of discipline at the plate, with significant swing-and-miss concerns. These pros and cons are backed up by FanGraphs, who give him a 50/60 grade for his raw power, but just a 20/30 grade for his hitting.

It's mostly all there to see in Peete's statistical output from last season, which was his first in High-A Everett. He hit a career-high 19 home runs, but produced just a .217 batting average and .692 OPS in 125 games. He also had 162 strikeouts for the second consecutive season, and a 32% overall miss rate for 2025.

Defensively there is reason for optimism with Peete, who was originally a shortstop when he was drafted and then saw some time at second and third base. The decision was made to put him in outfield full time last year, and thanks to his strength and athleticism he has been tremendous in the center field position and seems set to stay there.

For us, Peete remains a fascinating prospect, but objectively we can appreciate why Dipoto and company felt prepared to let him go to St. Louis. The physical skills are very much there, but if the Cardinals can't clean up his swing-and-miss issues, then he may never fully justify and take advantage of his talent.