The 49ers’ passing attack will be down to a skeleton crew when the team faces the Los Angeles Rams on Thursday night. Quarterback Brock Purdy and Ricky Pearsall and Jauan Jennings — the 49ers’ top two receivers so far this season — have all been ruled out with injuries. Unsurprisingly, the Rams have grown to 7-point favorites as this week has progressed and the 49ers’ gloomy injury situation has crystallized. After facing the Rams, the 49ers will travel to take on the Tampa Bay Buccaneers Oct. 12. That can boost the 49ers’ ailing run game, especially if Purdy, Pearsall, and Jennings also return to bolster the team’s passing threat.