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As the air quality in the Bay Area in Santa Clara nears the maximum threshold of a 200 AQI, 49ers practice on Friday hangs in the balance. Head coach Kyle Shanahan confirmed on KNBR on Friday morning, that the 49ers would also have to postpone their season opener if the air quality, as it is predicted to on Sunday, crosses the 200 threshold (Monday Night Football, maybe?).

But for now, the 49ers are still preparing to play Sunday, and Friday’s practice is crucial for Deebo Samuel, Brandon Aiyuk and Ben Garland. All three are effectively game-time decisions. Garland began practicing on Wednesday in limited fashion, and Aiyuk practiced Thursday. Samuel has yet to practice, but Shanahan told Murph and Mac he’s hoping he practices Friday.

As it stands, Aiyuk has a better chance of playing on Sunday (though, an extra day could help Samuel and Garland).

“We got Aiyuk out there yesterday and he looked good,” Shanahan said. “Deebo wasn’t able to get out there yesterday but the goal is to try and get him out today. Deebo is in a different situation not being a rookie compared to Aiyuk. Deebo got to play a ton last year. Even though he’s just going into year two, he got a good introduction to the league last year, so I don’t worry about him as much. If he’s healthy, he’s going to be good to go out there.

“But he’s got to get out to practice today and at least show us that. And Aiyuk, the fact that he got out yesterday, will give him another chance to get two days in. Aiyuk at least got a couple weeks in camp, so he has a better chance at least, of being there. Still, definitely a game day decision. Both of those guys and Garland, it’s going to come down to the wire with all of them.”

Traditionally, Shanahan doesn’t like to let players, unless they’re elite veterans like Richard Sherman or George Kittle, play in games after just one day of practice. It remains to be seen if Samuel falls into that category just yet.