Paxton (2-2) allowed five hits in eight innings, struck out two and walked two, and Carson Smith pitched a perfect ninth.
Miller snagged a hard hit groundball at shortstop from Dustin Pedroia to strand Blake Swihart at third base in the third inning. Swihart hit an inning-ending grounder with runners at second and third in the seventh inning.
Consecutive singles from Seager and Logan Morrison put runners on the corners with no outs in the second inning. Seager scored from third on a passed ball off Swihart's mask that went to the backstop, and Mike Zunino hit a two-out RBI single beyond the outstretched glove of Pedroia at shortstop.
Miller homered just inside the right field foul pole in the fifth for a 3-0 lead, his fourth home run in five games.
Red Sox: Masterson threw a long toss session prior to Sunday's game. Manager John Farrell said the inflammation in Masterson's right shoulder has lessened and he hopes to get Masterson back on the mound by midweek for some bullpen sessions before a rehab assignment.
Mariners: CF Austin Jackson went 2 for 4 for Triple-A Tacoma as he began a rehab stint Saturday night. Jackson has been on the disabled list since May 4 with a right ankle sprain. Jackson is expected to play the field for Tacoma for the first time on Sunday.
Red Sox: LHP Wade Miley (2-4, 5.60 ERA) will make his second-career start against the Texas Rangers on Tuesday. Miley lost his only decision against Texas despite allowing one run and three hits in 7 2/3 innings while with Arizona on June 13, 2012.
Mariners: RHP Taijuan Walker (1-4, 7.22 ERA) has held opponents to three runs or fewer in four of his last five starts.
MLB allowing five more teams to relax COVID-19 protocols after vaccinations
Five more major league teams are allowed to relax coronavirus protocols after 85% of their players and other on-field personnel completed vaccination for COVID-19, raising the total to 12 of the 30 clubs.
Fantasy baseball forecaster: Team hitting ratings
Stay ahead of the game and optimize your fantasy baseball hitters with our forecaster, which provides a rolling 10-day outlook of every team's hitting matchups as well as the potential for stolen bases.
Fantasy baseball forecaster: Pitcher projections for the next 10 days
Keep up to date on who is pitching -- and how well they're expected to do -- with our forecaster, which provides a rolling 10-day outlook of every team's probable starting pitchers with game score projections.
Why the Chicago White Sox are MLB's most interesting (and best) team
From a rookie with a burger named in his honor to a manager everyone loves to scrutinize, the South Side of Chicago is home to this season's most intriguing club.
Colorado hosts Cincinnati following Gonzalez's strong showing
Cincinnati Reds (17-18, third in the NL Central) vs. Colorado Rockies (14-24, fifth in the NL West)
Dodgers face the Marlins following Urias' strong showing
Miami Marlins (17-20, fourth in the NL East) vs. Los Angeles Dodgers (20-17, third in the NL West)