T-Mobile Park is a hitter’s house of horrors

Scary hours are 24/7 for hitters in Seattle this year.

This year, as in recent years, the Seattle Mariners have had a consistent, stalwart pitching staff attempting to hold off opponents just enough for a tepid offense to earn them the lead. Much of that is simply performance - Seattle has an above-average pitching staff anchored by a top-5 rotation that almost never provides uncompetitive outings. Meanwhile, their lineup entered the season without a slam dunk No. 3 hitter and they’ve seen mild to massive underperformance to expectations from most of their hitters. However, their home park has played a significant role in this gruesome and/or glorious display depending on the half inning. Yes, T-Mobile Park née Safeco Field has always been pitcher-friendly, but in 2024 it has genuinely been the antipodal park to Coors Field.

Baseball Savant

League-wide, offense is down once again, so comparing some traditional and/or unadjusted statistics needs that context. The infamous “Year of the Pitcher” in 1968 is the only season in MLB’s expansion era (1961—>) to have featured a lower league-wide batting average, with a .237 line in that ill-fated season (against .242 this year) and an astonishing .291 weighted On-Base Average (wOBA) league-wide that joins several years in the sixties and 1972 as the only seasons to skate under 2024 so far. Those years, of course, still featured pitchers hitting in both leagues, as the DH entered in 1973 to unequivocally improve offense in half the sport. Looking at purely non-pitchers, 2024 takes the cake for the worst batting average, and leaps all the way to 3rd-worst wOBA, outpacing only 1968 and 1967.

In short, before we stand agape at what we’re witnessing in Seattle, know that it is a sport-wide struggle and/or a sport-wide triumph of pitching development and usage to make hitting harder than it’s ever been, with the average fastball velocity now a blistering 94.4 mph.

But here in Seattle we are witnessing something extraordinary.

T-Mobile Park is on pace to host the highest full-season strikeout rate in the history (for the rest of the article, please treat “history” as 1961—> unless otherwise noted), with a punchout one in every 3.29 at-bats per Stathead, or 27.7% of all plate appearances. It is also on pace to be the worst park by batting average in history at .205, ahead of the ghastly 1967 White Sox Park at .207 whose 2.45 team ERA is the live-ball era record low (since 1920!). It would be one thing if folks could at least dip and rip here, but no, Seattle ALSO hosts the worst isolated power (ISO) in any full-time MLB park this year at .129, a power pace in line with sluggers like 2023 Jurickson Profar and Bryson Stott.

Watching hitting in Seattle in 2024, cumulatively, is akin to signing up for a non-stop barrage of 2013 Ike Davis. If you do not understand what a macabre affair that is, spare yourself the psychic damage and drag a Mets fan out of their Grimace-fueled euphoria to explain.

I will often write things encouraging folks to caution against their emotions. This is not that article. It is not that bad, it’s worse.

Of course, Seattle’s roster is not blameless here, far from it. But there are many players in the lineup striking out and underperforming in ways atypical to simple regression on batted ball luck. On the flip side, the Mariners have a great rotation and steady pitching staff striking out a Top-10 rate of opponents for the second-straight season, and for the third year in a row they’re punching out 23-24% of opponents. In fact, though it may beggar belief given their recent spate of impotence, Seattle’s pitching and the M’s bats have conspired to the degree that they’ve actually out-hit their opponents at home, with a .289 wOBA and a .212 BA as hosts, striking out 29.0% of the time, while Seattle’s opponents have had a staggering, league-worst-by-20-points .246 wOBA and .198 BA in Seattle, whiffing at a 26.6% clip.

The Mariners, in essence, have hit like 2012 Justin Smoak at home, while their opponents have hit worse than 2012 Brendan Ryan.

Things should improve in some aspects as the season goes on. For one, several players in Seattle’s lineup simply are liable to perform better based on their career track records, but it’s rightful to expect that this year will be record-setting in Seattle. Teoscar Hernández may have been onto something regarding the batter’s eye, or perhaps there’s some other issue, but the degree to which T-Mobile Park has become a death valley for hitters is unprecedented in the history of the sport. It’s hyperbolic to say “they always get worse” despite the frustrations M’s fans will lob at the club’s external acquisitions, and the organization does deserve significant scrutiny for their discount solutions struggling once again.

However, on average, yes, players should see their numbers backslide when they come to Seattle, more so than we may have even been able to believe given the way this year is going. The marine layer has gorged itself on hitters and become something new, fearsome, and untamed. If the Mile High Stadium is the zenith for hitters, T-Mobile Park is its Mariana Trench. When you gaze into the abyss, sometimes strikeouts stare back.