The teams will now play a two-game series at San Francisco's Oracle Park on Wednesday at 9:45 p.m. ET and Thursday at 4:10 p.m. ET. Seattle will be the home team and bat last in both games.
The Mariners and Oakland Athletics played a doubleheader in Seattle on Monday even though the ballpark was filled with a haze of smoke from wildfires raging along the West Coast and the Pacific Northwest.
Athletics left-hander Jesus Luzardo was upset about the playing environment, while Oakland manager Bob Melvin said MLB didn't provide any information about moving any of Monday's games due to the conditions.
Giants manager Gabe Kapler told The Associated Press his team was apprehensive about playing in Seattle.
"I think there was some concern, yeah, for sure," Kapler said. "Everybody was reading the reports on the air quality and we all wanted to be safe."
The Phoenix area has emerged as the primary backup option if MLB needs to move any postseason games due to air-quality problems, sources told Jeff Passan of ESPN. Los Angeles' Dodger Stadium and San Diego's Petco Park are currently scheduled to host 2020 playoff contests.