There are 2 Mariners prospects an insider wouldn’t want to trade

Jun 29, 2025, 11:41 AM

Editor, Seattle Sports

The Seattle Mariners have perhaps the best cache of prospects in baseball, which could come in handy with the July 31 MLB trade deadline nearing.

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The idea of an prospect that a team deems untouchable in a trade is rare, and that’s something that Aram Leighton, the co-founder and executive editor of Just Baseball, agrees with.

That doesn’t mean there aren’t Mariners prospects that Leighton thinks should be tough for the team to part with, though.

Leighton, who hosts The Call Up, an MLB prospect podcast, dove into two M’s minor leagues who he considers in that category when he recently joined Seattle Sports’ Brock and Salk.

“Even as the prospect guy, (I believe) you trade the prospects when you can and it’s gonna work in your favor,” Leighton told Mike Salk. “We’ve seen that with the Luis Castillo trade (by the Mariners) even as an example.”

Here comes the exception.

“But I look at a Colt Emerson, and the defense has gotten so much better at shortstop, and I think that’s a huge aspect of this whole thing,” Leighton continue. “Where if he’s sticking at short, takes some pressure off the bat, but that bat could be special (and) could accommodate a move to third.”

Colt Emerson with a Gold Glove play at shortstop! pic.twitter.com/wEaTyn3sv0

— Everett AquaSox (@EverettAquaSox) April 27, 2025

Emerson, Seattle’s top overall pick in the 2023 MLB Draft, is currently with High-A Everett and sits 14th overall in Leighton’s top 100 prospect rankings. While he started slow with the AquaSox this season, Emerson recently caught fire and won Northwest League Player of the Week honors.

“He’s starting to get hot here. He’s cutting it down on the ground ball rate, he’s hitting the ball hard,” Leighton said. “He’s still somehow still just 19. Emerson’s a guy that it would take something really special with (club control remaining on their contract) I think for me to move him. That’s the one guy that I look at and say I do not want to move him.”

Career-high FOUR knocks for Colt Emerson 🔥

MLB's No. 17 prospect (@Mariners) has 5 XBHs over his past two games after homering in his second straight contest for the High-A @EverettAquaSox. pic.twitter.com/G8X7Jnr2qT

— MLB Pipeline (@MLBPipeline) June 19, 2025

The other player Leighton mentioned is one of Emerson’s teammates and a fellow 2023 first-round pick: Everett outfielder Jonny Farmelo. Leighton has the 20-year-old Farmelo at No. 45 on his top 100 rankings, but he has a different reason for why he would not want to trade Farmelo now. That’s because a knee injury ended his 2024 season early and kept his 2025 season from starting on time, which could hurt his value in a deal.

“Johnny Farmelo I wouldn’t want to (trade) unless the organization that’s acquiring him values him as the player that we know he could be, had he been healthy for the second half of last year and through this year,” Leighton said. “So that’s a guy that I wouldn’t want to sell low on, but if the team really values him, that’s not gonna stop you.”

Hear the full Brock and Salk conversation with Just Baseball’s Aram Leighton in the video at the top of this post or audio player below. Catch Brock and Salk from 6-10 a.m. weekdays on Seattle Sports.