Alexander has made progress in his recovery from a pectoral tear that he suffered on Halloween to the point that the Niners now believe he has a good chance of returning for Saturday's NFC divisional round playoff game, league sources told ESPN.
The 49ers had not thought Alexander would be at this point in his recovery, but the former Pro Bowler has defied expectations just as Watt did during Saturday's wild-card game against Buffalo.
Watt knew and spoke about the risk of reinjury, and Alexander is aware of the same risk. But like Watt, he believes the risk is worth it.
Alexander was a surprise participant in the 49ers' bye-week practice Thursday. In conjunction with Alexander's appearance, the Niners opened his practice window to return from the injury, clearing the path for a possible return.
Niners coach Kyle Shanahan said this past week that Alexander is "coming along" in his recovery, adding that there is "definitely a chance" for the linebacker to return for the postseason.
Alexander, who was placed on injured reserve Nov. 5, is one of three 49ers defensive starters now expected to return next weekend. San Francisco also expects to get back pass-rusher Dee Ford (quadriceps/hamstring) and Jaquiski Tartt (ribs).
Ford, who recorded 6.5 sacks in his first year with the Niners, missed the final three games of the regular season, while Tartt was sidelined for San Francisco's last four games.