The San Francisco 49ers roster got more depleted on Wednesday, as they placed two more key starters, left tackle Trent Williams and wide receiver Brandon Aiyuk, on the reserve/COVID-19 list, per NFL Network's Mike Garafolo. The designation will cause them to miss Thursday's Week 9 contest against the Green Bay Packers.

Earlier in the day, wide receiver Kendrick Bourne was placed on the reserve/COVID-19 list after testing positive. The team shut down its facilities and started contact tracing, and will conduct the rest of their Week 9 preparation virtually.

Second-year wideout Deebo Samuel was also placed on the reserve/COVID-19 list, though he had previously been ruled out of the Packers matchup with a hamstring injury.

Samuel, Williams, and Aiyuk were placed on the list due to recent close contact with Bourne.

Without Samuel, Aiyuk was set to be the top receiving threat for second-string quarterback Nick Mullens on Thursday, while Williams offers essential protection on the blind side. San Francisco will likely start Justin Skule at left tackle.

The 49ers will also be without quarterback Jimmy Garoppolo (high ankle sprain), running back Tevin Coleman (knee), linebacker Demetrius Flannigan-Fowles (hamstring), and tight end George Kittle (foot fracture), who is expected to miss significant time.

The 49ers lost two key defensive linemen, Nick Bosa and Solomon Thomas, for the season on the same drive in Week 1 against the New York Jets.

As is stands, Trent Taylor and Richie James are the only two wideouts on the 53-man roster, and James is questionable with an ankle injury. The Nines can promote at least one wide receiver from the practice squad, possibly River Cracraft, Kevin White, or Chris Finke.

The shorthanded 49ers are 4-4 on the 2020 season, last place in the formidable NFC West.