Brandon Williamson has been promoted to Double-A Arkansas after striking out 47.6% of the batters he faced in six starts with the AquaSox this season. (Olivia Vanni / The Herald)

Brandon Williamson has been promoted to Double-A Arkansas after striking out 47.6% of the batters he faced in six starts with the AquaSox this season. (Olivia Vanni / The Herald)

AquaSox pitcher Williamson promoted to Double-A Arkansas

The 2019 2nd-round draft pick posted a 47.6% strikeout rate in 6 starts with Everett this season.

Everett AquaSox pitcher Brandon Williamson has been promoted to Double-A Arkansas, according to the Seattle Mariners’ player development Twitter account.

The 2019 second-round draft pick has a 3.19 earned-run average in 31 innings pitched this season, over the course of six starts with the AquaSox.

Williamson has been a strikeout machine, with 59 punchouts and just 10 walks. The 6-foot-6 left-hander has struck out 1.9 batters per inning and 47.6% of the batters he’s faced — both of which are the best marks by a wide margin among qualified pitchers in the six-team High-A West.

Williamson, ranked by MLB.com as the No. 9 prospect in the Mariners’ organization, has a 1.00 WHIP (walks plus hits per innings pitched) and a .189 opponents’ batting average.

The Minnesota native allowed five runs in one start this season and four in another. Over his other four starts, he yielded just two runs combined.

Williamson’s best outing came on May 29 against the Vancouver Canadians, when he allowed just one run and two hits in 7 1/3 innings. He struck out 13 of the 25 batters he faced in that game.

After being drafted by the Mariners out of Texas Christian University, Williamson made 10 appearances with the AquaSox in 2019, back when Everett was a Short Season-A club. He posted a 2.35 ERA in 15 1/3 innings that season, with 25 strikeouts and just five walks.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Sports

Kamiak senior Yegor Tarasov (left) jumps to head the ball Lake Stevens senior Shad Schmitt tries to defend him during Kamiak's 2-1 win in Lake Stevens, Washington on April 29, 2025. (Joe Pohoryles / The Herald)
Kamiak boys soccer spoils Lake Stevens senior night

The Knights improve their postseason odds while the Vikings lose their second in a row.

Monroe junior Julian Perez slips past a Snohomish defender before assisting the opening goal of the Bearcats' 4-1 win at Veterans Memorial Stadium in Snohomish, Washington on April 4, 2025. (Joe Pohoryles / The Herald)
Prep boys soccer roundup for Tuesday, April 29

Julian Perez scores four goals to keep Monroe perfect in league play.

Monroe’s Vivian Knuckey (22) swings during a 3A softball game between Monroe and Auburn Riverside at the regional athletic complex in Lacey, Washington on Friday, May 24, 2024. Monroe fell, 18-4. (Annie Barker / The Herald)
Prep softball roundup for Tuesday, April 29

Vivian Knuckey walks off a crucial league win for Monroe.

Prep roundup for Tuesday, April 29

Stanwood girls tennis dominates doubles for a league win.

Shorewood junior Ellie Van Horn winds up to deliver a pitch in the Stormrays' 12-0 win against Shorecrest in Shoreline, Washington on April 28, 2025. (Joe Pohoryles / The Herald)
Shorewood softball shows growth against crosstown rival Shorecrest

The Stormrays gear up for Wesco South gauntlet with a 12-0 win against the Scots.

Vote for The Herald’s Prep Athlete of the Week for April 20-26

The Athlete of the Week nominees for April 20-26. Voting closes at… Continue reading

Snohomish’s Morgan Gibson returns the ball in her match against Stanwood’s Ryann Reep on Friday, April 12, 2024 in Snohomish, Washington. Gibson lost the first set 4-6 but rallied back to win 6-2 in the second and 6-0 in the third. The Panthers bested the Spartans 5-2. (Taras McCurdie / The Herald)
Prep girls tennis roundup for Monday, April 28

Snohomish clinches fourth straight league title.

Jackson’s Allie Thomsen (22) celebrates a homerun during a prep softball game between Stanwood and Jackson at Henry M. Jackson High School on Tuesday, April 2, 2024 in Mill Creek, Washington. Jackson won, 6-0. (Annie Barker / The Herald)
Prep softball roundup for Monday, April 28

Allie Thomsen homers twice, strikes out nine in Jackson’s shutout win.

Seattle offensive lineman Charles Cross (67) looks on before the Seahawks take the field to face the Arizona Cardinals in an NFL game on Sunday, Nov. 24, 2024, at Lumen Field in Seattle. (Naji Saker / Tribune News Services)
Seahawks picking up 5th-year option on Charles Cross

The Seahawks have bought themselves a minimum of one more year with… Continue reading

Edmonds-Woodway pitcher William Alseth winds up on the mound against Lynnwood during an April 28, 2025 league game at Edmonds-Woodway H.S. (Courtesy of Jennifer Eklund)
Prep baseball roundup for Monday, April 28

Alseth throws run-rule perfect game for Edmonds-Woodway.

Prep roundup for Monday, April 28

Archbishop Murphy boys soccer overcomes Alex Plumis’ brace.

South Carolina's Nick Emmanwori was selected by the Seattle Seahawks in the second round of the 2025 NFL draft. (Dwayne McLemore / The State / Tribune News Services)
Seahawks draft class looks strong

The Seahawks had their most invigorating weekend in a long while. They… Continue reading

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.