San Francisco's running back luck just got a smidge less rotten.
Isaac Guerendo is officially active for the the 49ers' pivotal Thursday Night Football game against the Los Angeles Rams despite dealing with a foot injury on a short week.
Guerendo, who sprained his foot at the tail end of Sunday's 38-13 throttling of the Chicago Bears, was estimated as a non-participant in Monday's practice and sat out Tuesday's walkthrough before getting in limited work and receiving a questionable designation on Wednesday.
He figures to be a key part of the 49ers' game plan against L.A., even if they didn't need to fully unlock him until recently.
Injuries have simply destroyed San Francisco's backfield this season.
Weeks before reigning AP NFL Offensive Player of the Year Christian McCaffrey missed his first regular-season game amid a saga that kept him out of the team's first eight contests with an Achilles and calf injury, backup running back Elijah Mitchell went on season-ending injured reserve due to hurting his hamstring. Jordan Mason carried the load at the beginning of the year to tremendous results, but he left multiple games early because of shoulder issues.
During Mason's two prolonged in-game departures, in Week 6 against the Seattle Seahawks and Week 8 against the Dallas Cowboys, Guerendo flashed his potential with 24 carries for 184 yards and a touchdown.
He naturally receded into the background upon McCaffrey's return in Week 10. But CMC's comeback lasted only a month, as the RB suffered a PCL injury in Week 13 against the Buffalo Bills, a snowy, lopsided defeat in which Mason also suffered a high ankle sprain to eventually join his star running mate on injured reserve.
With the burden on him once more, Guerendo was game. The rookie speedster torched Chicago on Sunday for 78 rushing yards, 50 receiving yards and two scores before departing late, spelling yet another potential setback for coach Kyle Shanahan's operation.
Instead, San Francisco's fourth-string RB is healthy enough to continue on as its newest lead back.
His availability is a change in narrative for a snake-bitten club desperately looking to change its fortunes. With four games to go, the 49ers sit at 6-7, facing long odds (7%) to make the playoffs.
There's still a sliver of hope, though, something they'll try to expand upon when they square off against the rival Rams (7-6) at 8:15 p.m. ET on Thursday.