San Francisco’s running back luck just got a touch less bad.

Isaac Guerendo is officially the 49ers’ key player Football on Thursday evenings Played against the Los Angeles Rams despite a short week with a foot injury.

Guerendo, who sprained his ankle at the end of Sunday’s 38-13 rout of the Chicago Bears, was deemed a non-participant in Monday’s practice and had to sit out the walk-through on Tuesday before getting limited work and a questionable award on Wednesday .

He appears to be an important part of the 49ers’ game plan against LA, even if they didn’t fully unlock him until recently.

Injuries have simply destroyed San Francisco’s backcourt this season.

Weeks before reigning AP NFL Offensive Player of the Year Christian McCaffrey missed his first game of the regular season, he was forced to play in the team’s first eight contests because of an Achilles tendon and calf injury. Backup running back Elijah Mitchell was placed on season-ending injured reserve due to a hamstring injury. Jordan Mason put in a great effort and achieved excellent results at the start of the year, but left several games early due to shoulder problems.

During Mason’s two extended outings in the game, in Week 6 against the Seattle Seahawks and Week 8 against the Dallas Cowboys, Guerendo showed his potential with 24 carries for 184 yards and a touchdown.

After McCaffrey’s return in Week 10, he naturally faded into the background. But CMC’s comeback only lasted a month, as the RB suffered a PCL injury in Week 13 against the Buffalo Bills, a snowy, one-sided loss in which Mason also suffered a severe ankle sprain to finally join his star running mate in to join the injured reserve.

With the strain again, Guerendo was ready. The rookie speedster beat Chicago on Sunday with 78 rushing yards, 50 receiving yards and two scores before leaving late, marking another potential setback for coach Kyle Shanahan’s operation.

Instead, San Francisco’s fourth-best RB is healthy enough to continue as the new lead back.

His availability is a turning point in the story of a snake-infested club desperate to change its fortunes. With four games left, the 49ers are 6-7 and have a high chance (7%) of making the playoffs.

However, there is still a glimmer of hope that they will look to build on when they take on the rival Rams (7-6) on Thursday at 8:15 p.m. ET.