CB Chris Davis' unavailability was not unexpected. He has been unable to practice all week. Davis had been expected to be the 49ers' primary nickel corner and most likely would have been tasked with the duty of covering Rams WR Tavon Austin in the slot on Monday night.
OG Anthony Davis did not practice on Saturday due to what was described as a personal matter. He had practiced during the rest of the week. Davis is the starting right guard along the offensive line. Cam Inman of Bay Area News Group reports that Davis may once again be contemplating retirement – this time on the eve of the team's season opener.
CB Keith Reaser, who did not practice Thursday, was in full pads on Friday, but was limited. He too is listed as questionable.
Below is the complete injury report, which was released by the team. The status of "probable" was eliminated this season, leaving only "questionable," "doubtful," and "out."
49ers
Questionable: DT Arik Armstead (shoulder), LB Nick Bellore (knee), OT Anthony Davis (not injury related), DT Quinton Dial (knee), DT Glenn Dorsey (knee), CB Keith Reaser (ankle)
Doubtful: CB Chris Davis (hamstring)
Rams
Out: WR Pharoh Cooper (shoulder), CB E.J. Gaines (thigh), WR Nelson Spruce (knee)
Questionable: LB Bryce Hager (concussion), OT Rob Havenstein