T-Mobile Park is where baseballs go to die. We've known this for years, and the offensive struggles from seemingly talented Seattle Mariners rosters in past years are reminders that the Marine Layer remains undefeated. But this year, the Mariners' offense has been especially bad at home, while opposing offenses have been less bad. The difference between "especially bad" and "less bad" might not sound hugely important, but if the Mariners want to win the (very winnable) AL West and make noise in the postseason, that slight difference could mean everything. A small gap becomes a chasm.
It's hard to determine how good Seattle's offense really is in 2025 because of how drastic the team's hitting splits are at home versus on the road. At T-Mobile Park, the M's have an OPS of .672, which is No. 24 in baseball in home OPS. On the road, they are OPS'ing .759, which is third-best in the league.
Of course, the Mariners aren't the only team that struggles with the thick PNW air in Seattle; according to MLB Statcast, T-Mobile Park is the least hittable park in baseball (by a wide margin) over the past three seasons. But in 2025, that number has fallen a little bit, and the "park factor" in Seattle is ranked No. 22, which means, in short, that other teams are hitting in Seattle much better than the Mariners themselves.
That's not good news.
Seattle's offense is worse than visiting teams at T-Mobile Park
I'm getting ahead of myself here. But if the Mariners want a chance in the AL Playoffs, their pitching has to be nearly as sharp as it was last season — and so far, it hasn't been. Seattle's pitching has a home ERA of 3.90, is allowing teams to hit .248 at T-Mobile Park (compared to Seattle hitting .217) and has a WHIP of 1.29, which are all pretty close to the middle of the pack in MLB.
There lies the problem. If Seattle's pitching is going to be just okay at home, the offense has to be at least "just okay" too, despite how hard it is to hit at T-Mobile Park. If the Mariners win the AL West, there will be multiple playoffs games at T-Mobile Park, and as of now, the team still doesn't know how to hit on its own field.
But other teams are figuring it out! Last year, Seattle's pitching was No. 1 in ERA, WHIP and opponent batting average at home. It's important to mention that Seattle's pitching has been hobbling through the first two months of the season; George Kirby, Bryce Miller and Logan Gilbert have all spent time on the IL, causing the Mariners to give starts to less-effective pitchers.
But even when healthy, the Mariners pitching staff has to be historically good again if the offense is going to stumble like this at home, and asking an entire pitching staff to be basically the greatest rotation of all time just so a team can sneak into the playoffs isn't particularly fair, in my opinion.
Seattle's offensive woes might hold them back from division crown again
Last year, on June 3rd, the Seattle Mariners were 34-27 and had a stronghold on the AL West lead. At one point last summer, the M's had a 10-game lead over the Houston Astros in the division. That quickly dissipated and Seattle finished second in the divison, in large part because of an inconsistent and inefficient offense.
Right now, the Seattle Mariners hold a 0.5-game advantage in the AL West, fending off the hot Houston Astros — barely. There's no room for error, and if Seattle's offense fully bottoms out, the Astros could well take advantage and steal their eighth division title in nine years.
Hitting at T-Mobile Park is hard. Trust me, I have watched plenty of games at that ballpark in my lifetime to understand how brutal it is for batters. The batter's eye is (allegedly) crooked, the stadium sits right on the water to balls get bogged down and there isn't a "short porch" in left or right field.
But if this team wants to be taken seriously, they can't hit .217 at any ballpark, even one that's notoriously tough on hitters. Not when other teams are coming into Seattle and figuring out how to be at least passable.
Yes, asking a good professional baseball team to be passable at hitting baseballs is getting slightly irritating, thank you for asking.