Hirano told the Kyodo News on Tuesday that his placement on the injured list was the result of a positive COVID-19 test.
Seattle never provided an official explanation behind Hirano's move to the IL earlier Tuesday, though his absence from summer camp had already created suspicion that he might have tested positive for the coronavirus. According to the report, Hirano's positive test came all the way back on June 25, and he's since tested negative for COVID-19 on July 6. He'll need one more negative test result before he's allowed to rejoin the Mariners for workouts, but since he hasn't been able to train the past two weeks, Hirano will likely require some ramp-up time once he reports to the team before he's deemed ready for game action. With Hirano out of the Seattle bullpen picture at least temporarily, Matt Magill now looks like the favorite to open the season as the team's top closing candidate.