Doubling back, doubling down
The Mariners lineup is the best in baseball
The Mariners have the deepest and perhaps best lineup in MLB.
The lineup was already great. It’s difficult to size up a group that plays half its games in a magenta-splashed house of horrors, but the Mariners’ 110 wRC+ is fourth best in MLB and fourth best in team history. It’s been their strength for most of the season.
The lineup is now even better with Eugenio Suárez and Josh Naylor. With those additions, the Mariners’ active roster has posted 101.7 Batting Runs Above Average in 2025 — the most in MLB. They don’t get to retroactively assume the runs Suárez and Naylor delivered in Arizona (nor erase the days of Leody Taveras), but at the moment, the Mariners have the best collection of hitters in the league.
“This is the most complete team I think we’ve ever had, especially the lineup,” Logan Gilbert recently told Lookout Landing. “Top to bottom, I’ve never seen anything like it. It’s probably up there — if not the best, then one of the best in the league.”
More fun, less chum
Suarez’s 21.8 Batting Runs (143 wRC+) in Arizona make him the most productive hitter ever acquired by the Mariners midseason.
The path back to Seattle was unlikely for Suárez. The struggles he showed in 2023 continued into his first season with the Diamondbacks, where he posted a 66 wRC+ through June. He was even explicitly benched at one point. That summer, however, Suárez made some changes: he moved forward in the box, opened his stance, got out in front, and found the barrel again. He’s been one of the league’s best sluggers ever since.
That’s not to say there aren’t concerns for Suárez. The chart above shows he’s outpaced his expected results for large stretches of 2025. That’s partly explained by his elite ability to pull the ball in the air — he’s great at finding the shallowest part of the park to dump dingers. But he still whiffs a lot, as he did before, and the walks and defense are no longer there to prop up a homerless stretch.
Naylor’s 10.7 Batting Runs (121 wRC+) in Arizona make him the third most productive hitter ever acquired by the Mariners midseason (behind Suárez and Yonder Alonso in 2017). Naylor is not quite the slugger Suárez is, with more of a slasher approach in 2025 — protecting the zone, drawing walks and spraying line drives to all fields. But he’s proven capable of big home run power, with 31 for Cleveland last year.
It wasn’t initially clear what kind of impact Naylor could have in Seattle. The team has operated a platoon at first base for most of the season, most recently with Luke Raley and Donovan Solano. It worked on the strong side, with a 126 wRC+ at first base against righties (Naylor’s career mark is 122). But the weak side of the platoon produced a league-worst 40 wRC+ (Naylor’s career mark is 90).
With passable same-handed production, Naylor has become the Mariners’ full-time first baseman. They’ve pinch-hit just three times since he joined the team on July 25 — the fewest in MLB and a sharp departure from their record-setting pace.
New depths
The “starters vs. shufflers” paradigm the Mariners relied on in the first four months has now dissolved. In its place is a complete lineup, with nine batters who can play all nine innings nearly everyday. The group has been more productive than any other in MLB. The table below compares each team’s active roster (I manually added Aaron Judge to the Yankees’ active roster for the sake of comparison, as he’s set to come off the IL this week):
The Mariners lead MLB in both Batting Runs and wRC+. The Yankees are a close second, and both are well above the rest of the league. The Mariners’ lineup is also by far the deepest in MLB at the moment. They have eight batters who rank in the top 100 by Batting Runs — two more than the Yankees and Blue Jays in second place. That number doesn’t include Cole Young, who is one of the hottest hitters in MLB and could join the top 100 by year’s end.
A deep lineup can really wear down a pitcher with constant pressure over time, Dan Wilson said.
“There’s just no ability to catch your breath when you’re out there and when you’re getting constant traffic and the next guy up is also a solid hitter who can drive somebody in,” he said.
Depth doesn’t just help within games but between games, too. Most players are streaky and can slump for days or weeks at a time. We’ve seen that this year with Jorge Polanco, J.P. Crawford, Julio Rodríguez and, well, everybody — even Cal Raleigh. The Mariners have been more up than down overall in 2025, but there have been series where, by poor luck or poor play, not enough batters have clicked at the same time.
Suárez and Naylor simply give the Mariners two more plausible options to carry the team for a stretch. While either could slump at some point (neither has impressed since joining the club), the rest of the lineup affords them a bit of cushion. The Mariners can ride whatever hot streaks they inevitably provide without needing to rely on them every single game.
Final run
The Mariners at the deadline made a strength not only stronger but possibly strongest.
What they didn’t do was much else. They partially addressed the bullpen by adding Caleb Ferguson, but they also traded away reliever depth in their deals with Arizona. They didn’t touch the starting rotation and will instead bank on a previously top-rated group returning to form. And while Suárez and Naylor represent upgrades at the plate, neither helps a bottom-ranked defense. The way the Mariners have lost games this season — grounders leaking through the infield and middle-inning implosions — is likely the way they’ll lose games going forward.
But they aren’t the only team with issues:
The Astros’ recent skid has them below .500 over their last 30 games, and they may still be sliding with 17 players on the injured list. Even with Jeremy Peña back in the lineup, they have just two top-100 hitters, and their pitching has begun to fade.
The Mariners are now the best team in the AL West on paper. They’re projected to play two games better than the Astros the rest of the way. The gap is 2 1/2.