Suddenly, the Mariners Are Mashing

Though they’ve lost two straight to trim their AL West lead to a single game, the Mariners are a first-place team thanks to a recent 16-4 stretch that has boosted their record to 20-14. As I noted last week, their success for a change hasn’t been driven by the strength of their rotation, which has been without George Kirby thus far due to shoulder inflammation and is now without Logan Gilbert, who landed on the IL in late April with a flexor strain. Rather, Seattle been carried by an exceptionally potent offense, a marked contrast from recent years, particularly 2024, when the team’s failure to score contributed to the August firings of manager Scott Servais and hitting coach Jarret DeHart. These Mariners have benefited not only from Cal Raleigh’s heavy hitting, but from the ongoing presence of Randy Arozarena, who was acquired just before last year’s trade deadline, and rebounds from players who struggled due to injuries last season, such as J.P. Crawford and Jorge Polanco. The return of Hall of Famer Edgar Martinez to their coaching staff has helped, and it does appear as though T-Mobile Park has been a bit more forgiving than usual.

Raleigh and Polanco are the hitters getting the headlines. Raleigh is currently slashing .240/.359/.574 with a major league-high 12 homers, and he ranks third in the AL in slugging percentage behind only Aaron Judge and Alex Bregman, and fourth in the league in wRC+ behind those two and Jonathan Aranda(!). While Polanco doesn’t have enough plate appearances to qualify for the batting title because an oblique strain has limited him to swinging left-handed and to DHing instead of playing the field, he’s hit a ridiculous .369/.407/.750 (233 wRC+) with nine homers in just 92 plate appearances (14 short of qualifying). Crawford is batting .294/.417/.404 (151 wRC+) and Arozarena .224/.366/.414 (136 wRC+). Both players are walking over 15% of the time, with Raleigh drawing a pass 14.4% of the time; the team’s 11.2% walk rate leads the majors.

All of that has helped the Mariners withstand a comparatively slow start by Julio Rodríguez (.206/.308/.375, 103 wRC+) and a wave of injuries that has forced right fielder Victor Robles, outfielder-first baseman Luke Raley, utilityman Dylan Moore, and second baseman Ryan Bliss to the injured list alongside the aforementioned rotation stalwarts. Even so, the Mariners have gotten a 100 wRC+ or better from every position besides first base (where Rowdy Tellez, Donovan Solano, Raley and Moore have combined for a 60 wRC+) and right field (where six players, among them the injured Robles, Raley and Moore, have combined for a 90 wRC+).

Last year, when the Mariners fell one win short of a Wild Card berth, they ranked 10th in the AL in scoring at 4.17 runs per game, 14th in batting average (.224), and 12th in slugging percentage (.376), though they were a more respectable seventh in on-base percentage (.311) and tied for fifth with a 104 wRC+. It took a strong September to improve those rankings:

Given that the Mariners play in the majors’ coldest ballpark, the weather probably had something to do with their offensive troubles early last season as well as their offensive uptick in the summer, but the regime change may have been the real turning point. On August 22, when the team was 64-64, the Mariners fired Servais and DeHart, with Dan Wilson taking over as manager and Martinez, who previously spent 2015–18 as the team’s hitting coach, returning to that role for the remainder of the season. The Mariners went 21-13 the rest of the way, giving chase to a playoff spot that had once appeared out of reach before, alas, coming up just short.

As you can see from the table above, this season the Mariners are scoring at a similar clip to their late-2024 mark. They’re currently second in the league behind the Yankees both in that department and in wRC+. Martinez is no longer the hitting coach; instead he’s now their senior director of hitting strategy — a role that involves less travel — while Kevin Seitzer joined the staff as the hitting coach after 10 years in that capacity for the Braves. In Atlanta, Seitzer played a role in the success of MVP winners Ronald Acuña Jr. and Freddie Freeman as well as All-Stars Ozzie Albies, Matt Olson and Marcell Ozuna. Bobby Magallanes, who served as the assistant hitting coach under Seitzer in Atlanta from 2021–24, also made the move to Seattle.

While it’s fair to regard improvements in performance connected to coaching changes with some skepticism — correlation does not equal causation, and we’re still working with comparatively small samples in this case — anecdotal evidence suggests Martinez and Seitzer have had a substantial impact. Polanco may be the poster child for the new regime. After clubbing 33 home runs with a 124 wRC+ for the Twins in 2021, he played in just 302 games over the next three seasons due hamstring and knee injuries, and his performance eroded. Last year, he hit just .213/.296/.355 (92 wRC+) with 16 homers in 118 games, and his strikeout rate spiked to 29.2%, nearly 10 percentage points above his career mark. After the season, he underwent surgery to repair the patellar tendon in his left knee, a problem that contributed to his poor performance. This spring, with the help of Martinez and Seitzer, he closed his stance, reducing the angle at which his feet deviate from a straight line to the pitcher. The changes have not been symmetrical; batting left-handed, he’s reduced the angle from 37 degrees to four, while batting right-handed — something he hasn’t done in a game since March 31 — he reduced the angle from 19 degrees to 14.

Updating what Davy Andrews recently wrote about Polanco batting lefty, he’s increased his average bat speed a bit (from 70.2 mph to 71.9), his fast swing rate from 8.6% to 20.8%, his squared-up rate from 23.1% to 35.4%, and his blast rate from 9.4% to 20.8%. His average exit velocity has increased by nearly 4 mph, his barrel rate has more than doubled, and his xSLG has improved by over 300 points:

In the compilation video below, which shows one home run from 2024 and then two from this season, you can see the extent to which Polanco’s stance has closed:

The change — first detailed by MLB.com’s Mike Petriello — was driven by residual soreness in his surgically repaired knee, but it’s fit in with the mechanical and philosophical adjustments imparted by Martinez and Seitzer.

“When Edgar got here, he just preached on that [middle-of-the-field] approach,” Polanco told MLB.com’s Daniel Kramer after homering twice against the Angels last Tuesday. “Everybody knew who Edgar was, so we just listened to him, trying to work on that. So I took it into the offseason.”

“Guys that start open can have a tendency to turn too much and maybe block themselves, stride in at times, and not be consistent with their direction,” Seitzer told Kramer. “I like simplified — when guys get in a good position when they get into their weight transfer, they get to their heel plant, they’re in a good position to fire from their body position and into their hands.”

Variations on the word “simple” pop up frequently in descriptions of the way that Martinez and Seitzer have communicated with hitters.

“I just think how simple Edgar kept it,” Raleigh told the Seattle Sports podcast in February when asked how Martinez had helped the team’s hitters. “At the end of the day, just doing your job, staying to the big part of the field. Really just simple messaging… As hitters, as all of us do, sometimes we get a little too analytical or thinking about the swing too much. It doesn’t come down to that.”

“Seitz teaches simple things in simple ways, and he’s so subtle in how he goes about it,” president of baseball operations Jerry Dipoto told The Athletic’s Tyler Kepner. “I’ve joked that he’s Midwest Edgar.”

Raleigh’s swing and stance metrics haven’t changed appreciably from last year. The switch-hitting backstop is hitting the ball harder than usual from the left side, which may or may not have something to do with his recent adoption of the torpedo bat. Raleigh began using it — but only against righties — on April 11, kicking off a stretch of six home runs in six games vs. the Rangers and Reds; five of those homers came against righties. Relative to what he’d done from that side of the plate over the season’s first two weeks, since the change he’s gained over 3 mph of exit velo, tripled his barrel rate, and more than doubled his xSLG:

Torpedo bat or no, Raleigh’s overall 22.5% barrel rate is in the 99th percentile of all hitters. Meanwhile, his 36% pulled air rate leads the majors, and breaks down to a 41.7% rate as a lefty (tops in the majors by over nine points!) and 24.1% as a righty. Polanco (30.7%) ranks ninth in pulled air rate, with Arozarena (26%) and Moore (25.9%) 31st and 32nd, respectively.

On the subject of pull rates, one theory about the Mariners’ recent history of offensive struggles is that their hitters have been too pull-happy, perhaps feeling as though they needed to get every advantage available in order to hit balls out in a park where the conditions — temperature, humidity, elevation, wind — reduce carry on fly balls. Last year, the reduction was by an estimated 5.3 feet, the second-largest shortfall in the majors, and according to Petriello — who did a deep dive on the offense-suppressing nature of T-Mobile Park in January — it cost the Mariners and their opponents an estimated 55 homers, also the second-largest total.

The Mariners offense was very successful while pulling the ball more frequently than any other team in 2023, but that approach didn’t work last year. Indeed, it was said to be a factor in the tepid performance of Rodríguez. Via the Seattle Times’ Ryan Divish:

Rodríguez seemed to lose himself as a hitter in his struggles. The metrics said he was at his best when pulling the ball in the air, but it didn’t feel natural for him to try and pull it. But it also didn’t feel right to just focus on hitting in any direction. His swing changes from the previous offseason left him off balance and looking unathletic.

Rodríguez hit just .263/.314/.369 (102 wRC+) while pulling the ball 32.2% of the time (13.9% in the air) before Martinez took over, but .303/.353/.520 (151 wRC+) thereafter while boosting his overall pull rate to 36.4% and his pulled air rate to 22%. “For Rodríguez, they simply wanted him to hit the ball with authority and not try to worry about whether it was in the air or to a specific part of the park,” wrote Divish. “Martinez also convinced Rodríguez to move his hands slightly and focus on being more athletic and balanced in the batter’s box.”

In March, Seitzer spoke of the way that T-Mobile Park might be getting in hitters’ heads. He told the Seattle Times’ Adam Jude:

“You have to embrace where you play (your home games),” Seitzer said. “When it is the way it is, we’ve just got to focus more on low line drives – just making solid contact and not worrying about balls that we crush that should be homers that get caught. There’s nothing we can do about it. But as long as we’re squaring balls up, having good at-bats and putting the fat part of the bat on the ball consistently, that’s all you can do.”

Now Rodríguez is pulling the ball 38.8% of the time, but pulling it in the air a career-low 12.6% of the time; his groundball rate is at a career-high 50.5%, so the Mariners still have work to do to help him get right.

While Mariners hitters are getting better results with a different set of voices preaching a different approach — and players such as Polanco and Crawford are healthier than last year — it’s also worth noting that at least in the early going, T-Mobile has been more hitter-friendly than last year, both to the Mariners and their opponents. Through 18 home games, the estimated reduction in fly ball carry based on the surrounding conditions is just two feet, the ninth-largest shortfall. Using May 5 as a cutoff for each season, actual average fly ball distances are up one foot over last year, and five feet over 2023, while those for pulled fly balls are up four feet over last year, and 13 feet over ’23, though scoring rates are similar to what they were in the latter year.

Note that strikeout rates are down as well, though I don’t think the Mariners have done anything to address the complaints about the batter’s eye that date back to the heyday of Martinez and Ichiro Suzuki and were most recently voiced by Teoscar Hernández, who struggled during his 2023 season with the team.

It may be a stretch to say that it’s taken a perfect storm of players, coaches, and environmental conditions for the Mariners to upgrade their offense. Even so, it’s not hard to identify the gains they’ve made in those areas as factors. With Kirby and Gilbert taking steps forward in their respective rehabs — the former started for Triple-A Tacoma on Sunday, while the latter has ramped up his long-toss regimen — there’s hope that the pitching staff can round into shape as well. It’s too early to anoint the Mariners as the team to beat in the AL West, but after barely missing out on playoff spots following slow starts in 2023 and ’24, this is certainly an improvement.