The 49ers might be without yet another defensive starter Sunday against the Los Angeles Rams.
Linebacker Kwon Alexander has a possible high ankle sprain, 49ers coach Kyle Shanahan told reporters on a video conference call Monday. Shanahan said the 49ers will know the full nature of Alexander's injury by Wednesday.
"They're not sure of the severity of it," Shanahan said of the 49ers' medical staff. "It could be a minor one for whatever that means. So, that's why, usually if it was automatic high ankle sprain, I'd be talking about [injured reserve] and stuff right now, but they told me to hold on that because they think it possibly could be a minor one. Don't know. They’ve got to do more work today on it and we'll have an answer on that for Wednesday.”
Alexander, 26, has played in no fewer than 87 percent of the 49ers' defensive snaps in a single game this season. He's second on the team in combined tackles (30) and third in tackles for loss (three).
Should Alexander not play Sunday at Levi's Stadium, the 49ers will be without (at least) one of their typical starters at every level of the defense. Edge rusher Nick Bosa is out for the remainder of the season after sustaining a torn ACL in Week 2 against the New York Giants, while cornerback Richard Sherman -- who hasn't played since Week 1 -- likely is out after suffering a setback.
The 49ers are optimistic cornerback Emmanuel Moseley will be cleared from the concussion protocol, but top nickel cornerback K'Waun Williams was placed on IR last Saturday and defensive lineman Solomon Thomas is out for the rest of the season after sustaining a torn ACL in the same game as Bosa.
The 49ers allowed 43 points to the Miami Dolphins with Alexander in the lineup in Week 5, and their struggling defense can't afford to lose any additional starters at this point. Sean McVay's Rams are up to their old tricks so far this season, scoring 27.2 points per game so far.
If Alexander's potential absence is any indication, the 49ers defense's season-long battle with injuries is showing no signs of getting any easier.