Samuel on IR, must sit at least 3 games

The 49ers placed Deebo Samuel on shortterm injured reserve Saturday due to the broken foot their top wide receiver suffered in midJune.

Samuel, who had a Jones fracture, is eligible to return in Week 4 when the 49ers host the Eagles on Oct. 4.

The 49ers weren’t initially able to place Samuel on shortterm IR to open the season because he was on the nonfootball injury list during training camp. However, the NFL adjusted that rule Thursday night, meaning players such as Samuel who were on the NFI list before the season are now eligible to be placed on shortterm IR.

This season, teams are permitted to place an unlimited number of players on shortterm IR because of potential roster needs caused by the coronavirus pandemic.

Head coach Kyle Shanahan said Friday, after Samuel was ruled out of Sunday’s season opener against the Cardinals, that optimism for Samuel playing dimmed during the week.

“We believed he had a good chance to play this week,” Shanahan said. “It didn’t go the way we hoped.”

The 49ers are expected to host the Arizona Cardinals in their season opener Sunday at Levi’s Stadium in unhealthy air quality that falls below the NFL’s threshold to consider canceling a game.

Spokesperson Kristine Roselius of the Bay Area Air Quality Management District said Saturday the air quality index in Santa Clara on Sunday is projected to fall between 151 and 200, which is classified as “unhealthy for all groups.” Roselius noted Sunday’s AQI could change because “wildfire smoke is very unpredictable.”

The AQI in Santa Clara on Saturday afternoon was 181, according to airnow.gov.

The league would consider calling off a game if there is “definitive evidence” the AQI

The 49ers’ decision to place Samuel on IR could have been influenced by their upcoming schedule. Their next two games after Sunday, at the Jets and Giants, will be played on artificial turf at MetLife Stadium.

Samuel, a 2019 secondround pick, had the most receiving yards (802) by a 49ers rookie since Jerry Rice in 1985 and the most rookie receptions (57) since Earl Cooper in 1980. He also led NFL wide receivers in rushing yards (159).

The 49ers also promoted center Hroniss Grasu and cornerback Dontae Johnson from the practice squad. Grasu received the callup with center Ben Garland (ankle) questionable with an ankle injury. Cornerback Jason Verrett (hamstring) has been ruled out.

The fact that the 49ers didn’t promote one of their three practicesquad wide receivers bodes well for rookie Brandon Aiyuk’s availability. The firstround pick is questionable with a hamstring injury he suffered Aug. 23. Aiyuk returned to practice Thursday and was limited during the week.

Eric Branch covers the 49ers for The San Francisco Chronicle. Email: ebranch@sfchronicle.com Twitter: @Eric_Branch will remain above 200 at the stadium for a significant period of time on game day. NFL spokesperson Brian McCarthy said Saturday the game remains on schedule and the league will continue to monitor conditions.

Running back Tevin Coleman didn’t practice Friday because the AQI was in the unhealthy range and head coach Kyle Shanahan said Coleman will have to make a choice about playing if the air quality index is at 150 or above Sunday.

Coleman has the sickle cell trait and is particularly sensitive to air pollution and low oxygen levels.

Eric Branch covers the 49ers for The San Francisco Chronicle. Email: ebranch@sfchronicle.com Twitter: @Eric_Branch