Week 9 Fantasy Baseball Waiver Wire: Prospect parade continues with Colt Emerson

Another top prospect gets the call. This time, it's Mariners shortstop Colt Emerson

Chris Towers

May 17, 2026

6:11 pm ET

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14 min read

Mark J. Rebilas

The Mariners gave Colt Emerson a chance to win a job out of Spring Training. And then they gave him a $95 million contract back in early April. They've wanted him on the major-league team for a while, and we've been waiting for him to get the call.

And now he's finally here.

Emerson is the Mariners top prospect and a consensus top-20 guy across baseball, and he'll be making his MLB debut Sunday, nearly two months shy of his 21st birthday. If you know nothing else about Emerson except that he's about to make his MLB debut as a 20-year-old, you should already be pretty excited about him. And, of course, the skill set is plenty exciting in its own right.

Emerson has nine homers and 11 steals in his first 44 games at Triple-A, showcasing a very Fantasy friendly skill set already. And there's room for him to grow into some more power as he ages, though he's already registering close to average exit velocity readings as a 20-year-old, which isn't bad. If it all comes together, Emerson could be one of the best hitters at the position – Scott White hit him with a lofty Corey Seager comp in his preseason top-100 prospects list, which had Emerson No. 10 overall.

Emerson is hitting just .255 at Triple-A, you may notice, with an elevated 27.2% strikeout rate. But this isn't a case of a young player struggling with contact against minor-leaguers who is about to be exposed by big-leaguers – his contact rate on pitches in the strike zone is 86.5% and he's showing at least average power to go along with it. The issue is that he tends to be a bit overly aggressive, but he makes enough contact and does enough with it when he does that scouts don't think it'll be something he can't overcome.

It might be too much to expect Emerson to be a true superstar from Day One, of course, but that kind of outcome is possible from any top prospect. The Mariners are calling him up because they need a spark, and he's likely to open his career as the team's everyday third baseman for as long as Brendan Donovan is on the IL -- and he could shift over to either shortstop or second base if he's good enough to force the issue. The best-case scenario here could look something like recent top prospect JJ Wetherholt's first season, where the batting average has been a bit of a drag, but he's doing enough else well to be viewed as a must-start Fantasy option. It'll be easier to make that call for Emerson once he gains third base eligibility, though he would still certainly rank below another top prospect, Kevin McGonigle, there.

But Emerson is the kind of prospect worth adding in all leagues just in case he hits his high-end outcomes, especially at a third base position where few teams have no need for an upgrade. Emerson's aggressive approach at the plate could hold him back, but if he makes enough contact, he could play his way into top-12 status at third in short order.

Here's who else we're looking to add when waivers run for Week 8:

Week 9 Waiver Targets

Catcher

Gabriel Moreno, Diamondbacks (43%)

After it looked like he might have taken a step forward last season, it's been a frustrating season for Moreno so far. Injuries haven't helped, but he's also hitting just .228/.276/.354, with both a career-high strikeout rate and career-low walk rate on his ledger. If you're looking for a hot-hand play, in other worse, you won't find it with Moreno (though he does have multiple hits in his past two games entering play Sunday). But if you're looking for something with a little more long-term outlook, I still believe Moreno can get right and get back to being a productive hitter like we saw last season.

Deep league option: Jesus Rodriguez, Giants (15%) – Here's an interesting question for you: How much does Buster Posey's faith in Rodriguez matter to you? Rodriguez had only been in the majors for about a week before the Giants opted to move Patrick Bailey, a show of faith in their young catcher … who has gone hitless over the past week entering play Sunday. If you're looking for another longer term play with some upside, Rodriguez qualifies, even if he hasn't shown much so far. The larger track record of his minor-league career, where he hit .311/.396./.452 with 20-steal potential is still intriguing.

First Base

Casey Schmitt, Giants (60%)

There are some widely available first basemen who have some long-term upside but aren't doing much right now, like Spencer Torkelson. But if you need immediate help, Schmitt has played well enough that the Giants have changed many of their infield plans to accommodate getting him in the lineup regularly. He was slowing down a bit early in May, but then he went off for a four-hit, two-homer game Saturday, so he isn't fading out just yet. Helping his cas