Coach Mike Macdonald said Monday that Arnold’s visit and tryout went well.
The Mariners avoided losing seven straight for the first time since 2020.
Randy Arozarena hit a two-run homer and Julio Rodríguez connected for a solo shot.
Seattle right-hander Bryan Woo went five innings in his second consecutive scoreless start.
Zia Cooke finished with 16 points off the bench for Seattle.
Emerson Hancock (6-7) gave up two runs on nine hits over 4 2/3 innings.
Gov. Bob Ferguson has declared late last month that August is Emergency Management Awareness Month in Washington state.
Farinacci, 37, is charged with starting the Old Trails fire, one of three blazes in the Spokane area that have burned more than 850 buildings, destroying whole neighborhoods and streets. No deaths or serious injuries have been reported.
Andrés Muñoz pitched a 1-2-3 ninth, striking out two to earn his 20th save this season.
Seranthony Domínguez allowed four runs while only recording one out in his Mariners debut.
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