Grading the road-warrior Seattle Mariners' impressive 2-1 series win vs. Boston Red Sox

The Seattle Mariners are flying home on Thursday with something they haven’t had in over a decade — a series win at Fenway Park.

For the first time since 2014, the Mariners took a series in Boston, capping off a highly successful East Coast road trip that saw them go 6-3 against the Toronto Blue Jays, Cincinnati Reds and, finally, the Red Sox. 

With three straight series wins on the road under their belt — and five in a row overall — the Mariners now sit at 14-11, three games over .500 and trending upward. As they return to Seattle with momentum, let’s break down the series grades from their series in Boston. What clicked, what didn’t, and who stood out along the way?

Mariners vs. Red Sox Breakdown and Grades: Series Results

• Tuesday, April 22: SEA 3, BOS 8
• Wednesday, April 23: SEA 8, BOS 5
• Thursday, April 24: SEA 4, BOS 3

Grading the Mariners’ Offense: B

Grading the Mariners’ offense in this series comes with a bit of context — they were playing at Fenway Park, one of the most hitter-friendly ballparks in the league. That said, Seattle did a solid job of capitalizing on the environment. After a quiet opener in which they managed just three runs, the bats came alive with an eight-run outburst in Game 2 and a solid four runs in the finale.

The most surprising and encouraging results were the production that came from the bottom of the order. Ben Williamson continued to make a strong impression in his first trip to Fenway, tallying five hits over the series. J.P. Crawford remained red-hot at the plate, raising his batting average to .260, highlighted by a 2-for-4, 4-RBI performance in Game 2. Even Leo Rivas chipped in, collecting hits in back-to-back games and quietly boosting his average.

In the finale on Thursday, the 7-8-9 hitters (Williamson, Rivas, and Crawford) combined to go 5-for-11 with two walks, consistently setting the table for the top of the lineup.

That kind of contribution from the lower third of the order — a group that has often been a weak spot — helped balance the lineup and made the Mariners a more complete offensive threat. While the top four to five hitters are usually the ones carrying the load, this series win doesn’t happen without the bottom half stepping up.

Grading the Mariners’ Defense: B-

The Mariners’ defense was mostly steady throughout the series, committing just one error across the three games. Unfortunately, that one miscue was unforgivable.

In Game 1, Rivas sailed an errant throw to first base on a routine play, allowing Carlos Narváez to score and stretch Boston’s lead to 8-3 — effectively slamming the door on any late-inning comeback. It wasn’t the play that lost them the game, but it was certainly the one that sealed it.

Outside of that mishap, Seattle’s defense showed flashes of polish and progress. Williamson continues to impress at third base, making several standout plays that simply wouldn’t have been made by the carousel of players manning the position earlier this season. His instincts, range, and reaction time are beginning to make the hot corner look like his for the taking — and it’s getting harder for the Mariners to justify taking him out of the lineup.

Communication on fly balls also appears to be improving, a small but important step for a team that’s had its share of defensive miscues early in the season.

Still, there are some ongoing concerns, especially at first base. Rowdy Tellez has been surprisingly nimble with the glove when he’s in there, but he only starts against righties. Donovan Solano, on the other hand, has looked out of place at times — with shaky footwork, questionable reads, and awkward glove positioning.

It’s clear that this is still a bit of a patchwork infield, especially on the right side. But compared to the early weeks of the season, the improvement is noticeable — and if Williamson keeps anchoring the left side, that defensive floor will continue to rise.

Grading the Mariners’ Pitching: B-

On paper, giving up 15 runs over a three-game series doesn’t scream success — but the full story paints a more nuanced picture for Seattle’s pitching staff.

After a rough opener in which they surrendered eight runs, the Mariners regrouped quickly and executed a much more aggressive approach. They pounded the Red Sox lineup with high-velocity fastballs in the second and third games, and the adjustment paid off.

Game 1 exposed an issue that’s been surfacing with Bryce Miller, whose velocity dip has become a concern in recent outings. He struggled to keep Boston’s bats quiet, and the Red Sox made him pay. But in Game 2, Emerson Hancock flipped the script with his best start of the year. He delivered a quality start, tossing six innings of two-run ball while scattering five hits, walking two, and striking out seven — showing a noticeable uptick in velocity and command.

Game 3 saw Bryan Woo match up against Boston ace Garrett Crochet — and Woo didn’t blink. He spun a gem of his own, allowing just two runs across six innings on three hits with one walk and eight strikeouts.

The pair of quality starts from Hancock and Woo marked the first time two Mariners starters had posted back-to-back quality starts in Boston since Jamie Moyer and Freddy Garcia did it in [checks notes] 2001 — a wild stat courtesy of Aaron Goldsmith that speaks to both promise and underperformance from this rotation in recent years.

One lingering concern is Trent Thornton, who continues to look shaky in high-leverage spots. Manager Dan Wilson made a smart adjustment by using him for a single batter (Alex Bregman) in the eighth inning of Game 3, rather than trusting him with a full frame. That’s likely the right formula going forward: low-leverage situations until Thornton proves he can navigate traffic without imploding.

Grading the Mariners’ Strategy: C

Wilson’s game management in the final two contests of the series deserves some credit, and likely helped nudge the Mariners toward back-to-back wins. But overall, his strategic decisions continue to be a mixed bag.

The grade gets a bump largely due to adjustments made in the bullpen. Wilson showed growth by steering away from the high-leverage usage of Thornton and instead leaned on more reliable arms like Gabe Speier and Collin Snider before eventually handing the ball to Andrés Muñoz. That shift in sequencing played a critical role in closing out the final two games.

However, Wilson’s handling of the bench continues to raise questions. He tends to burn through his substitutions early — often by the sixth or seventh inning — leaving little flexibility down the stretch. That aggressive approach hasn’t consistently yielded results.

Case in point: removing the surprising Dylan Moore in Game 3 in favor of Miles Mastrobuoni — a player with solid plate discipline but nowhere near the same offensive upside. Similarly, continuing to give late-game at-bats to Donovan Solano, who’s hitting just .086. Chances are higher just allowing Tellez to stay in the box in a lefty-lefty matchup.

The issue isn’t necessarily that Wilson is leaning into analytics — it’s that the matchups don’t always make sense when the players he's removing are actually performing well. There’s a fine line between being proactive and overmanaging, and right now, Wilson occasionally strays into the latter.

The Mariners organization — and Wilson — still have some evaluating to do when it comes to maximizing their bench. But for now, with the team sitting three games over .500 and riding the momentum of five straight series wins, they’ll take the positives where they can.

No rest for the weary. Thursday’s day game doubled as a getaway day, and Seattle will be back at it Friday night at home to open a three-game set against the Miami Marlins.

At 11-13, the Marlins have been more competitive than expected. While they may not be postseason favorites, they’re no pushover — and this upcoming series won’t be a free pass. The Mariners will need to carry their momentum into the weekend if they want to keep their series winning streak alive.