Donovan's arrival will be felt throughout Mariners' lineup

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 -- The Mariners were already comfortable with their roster heading into Spring Training before Monday’s splashy trade to acquire Brendan Donovan.

But they were admittedly vulnerable at two key spots before finally prying the infielder/outfielder from the Cardinals as part of a three-team deal with the Rays -- and perhaps even more so, with the potential pressure on young infielders Cole Young and Colt Emerson to perform right away for a team with World Series aspirations.

That tandem -- Seattle’s first-round Draft picks in 2022 and ‘23, respectively -- might be among the most discussed when position players hold their first workout on Feb. 12. But the Mariners’ front office has made it clear that it will give both a runway to a role on the ‘26 roster while continuing their development.

The bridge to those two is one of the myriad reasons the Mariners coveted Donovan -- and why he will be a big part of the club’s quest to defend its American League West title.

Donovan will play all over
The 2025 All-Star will be Seattle’s everyday leadoff man but defensively he’ll move around the diamond based on matchups impacting other positions, according to sources familiar with the club’s thinking. He’s slated to be their primary third baseman entering Spring Training, but that could change based on positional competitions -- specifically among Young and Emerson, MLB Pipeline’s No. 9 overall prospect.

With first base (Josh Naylor) and shortstop (J.P. Crawford) solidified, the other two spots will be in a sort of flux -- for now. Leo Rivas’ switch-hit and multi-positional versatility makes him a virtual lock for a backup spot.

Young has the leg-up to make the team and would have to struggle mightily to lose his grip on the second-base job, while Emerson -- a natural shortstop who can play all over -- could still need seasoning by Opening Day. But that’s expected to be the leading tandem worth watching from a roster construction standpoint.

Regardless, Young, 22, and Emerson, 20, could wind up benefiting mightily longer-term, as Donovan’s presence eases some burden on them. The Mariners are bullish on Young being their second baseman of the future, and Emerson has as much upside as any position-player prospect in Seattle since Julio Rodríguez.

But Donovan, in the club’s eyes, can serve as that ideal bridge to the young pair, given that he’s under club control for two years and at an affordable $5.8 million for 2025.

There will be platoons elsewhere
But not with Donovan, who sported an .853 OPS vs. righties and .614 OPS vs. lefties in 2025. No, the rest of the matchup-dictated positions will primarily be in right field and at designated hitter, where the Mariners have four such players -- lefty-hitting Dominic Canzone and Luke Raley, and righty-hitting Victor Robles and Rob Refsnyder, who was signed to a one-year, $6.25 million contract on Dec. 22.

As it stands, Raley and Robles -- the better defenders -- will split action in right field, while Canzone and Refsnyder will do so at DH. But obviously, injury possibilities and in-season struggles will keep those plans in motion.

Emerson and Young each bat left-handed, too, and there’s a likelihood that the Mariners will avoid using either against the sport’s better southpaws. That’s also where Donovan could move around the diamond to fill those positions on a day-by-day basis. He will also be Naylor’s primary backup at first base.

Projected lineups
Here’s what the Mariners’ lineup could look like vs. right-handed pitching:

1. Brendan Donovan, 2B/3B
2. Julio Rodríguez, CF
3. Cal Raleigh, C
4. Josh Naylor, 1B
5. Randy Arozarena, LF
6. Dom Canzone, DH
7. Luke Raley, RF
8. Cole Young/Colt Emerson, 2B/3B
9. J.P. Crawford, SS

And left-handed:

1. Brendan Donovan, 2B/3B
2. Julio Rodríguez, CF
3. Cal Raleigh, C
4. Randy Arozarena, LF
5. Josh Naylor, 1B
6. Rob Refsnyder, DH
7. J.P. Crawford, SS
8. Victor Robles, RF
9. Leo Rivas, 2B

What about Donovan’s hitting?
While Donovan won’t make up for the power production lost from the departure of Jorge Polanco -- who crushed 26 homers with an .841 OPS last year -- Seattle’s new addition does directly address an area that the club has zeroed in on in recent years: strikeouts.

Donovan, who had 10 homers in 2025, also sported a 13% K rate that would’ve easily been the best on the team, and he ranked in Statcast’s 95th percentile in whiff rate (13.4%). He profiles as a gap-to-gap and doubles hitter, which will present its own challenges at T-Mobile Park, where extra-base hits can be suppressed. But the Mariners haven’t quite had a hitter with his profile -- at least a proven one -- in some time.

And his defense?
Although he was primarily a second baseman in St. Louis (225 games), that was out of roster viability, as the Cardinals had 10-time Gold Glove Award winner Nolan Arenado at the hot corner. Donovan also has experience at first base (30 games), third base (46), shortstop (14), left field (163) and right field (30). He’s graded as mostly average at every spot.