Once again, the San Francisco 49ers have been one of the most disappointing teams in the NFL.Kyle Shanahan's squad has failed to replicate the success they found a couple of years ago when they made it to the Super Bowl.And, while their offensive struggles and questionable play-calling at times could be to blame for that, it's also worth noting that they've been one of the unluckiest teams with injuries.Now, they could miss the chance to get back to .500 for the first time since Week 4, precisely because of an injured player.49ers Rookie Elijah Mitchell Could Be Out With A Broken FingerThe 49ers' offense has relied mostly on its running game. They currently rank 13th in the league in rushing yards per game at 117.9.Most of those yards come thanks to sensational rookie Elijah Mitchell, who has rushed 116 times for 560 yards and 3 touchdowns over 7 games.Sadly for them, Matt Maiocco of NBC Sports reported that his status for Sunday's clash vs. the Jacksonville Jaguars is in question after undergoing a procedure to repair a broken finger."Coach Kyle Shanahan does not know when Elijah Mitchell was injured. He has played through some tough injuries already this season. He made no mention of the finger injury until this morning," Maiocco added.Jimmy Garoppolo Laud Mitchell's ToughnessMitchell has become a focal point in Shanahan's offense and has earned the respect of his peers for his toughness and work ethic.“This guy — he’s a battler,” QB Jimmy Garoppolo told The Athletic.“For him to battle the way he has through injuries — and all the guys are dealing with that — but he’s done a good job of that stuff. It’s impressive.”That toughness is why there's still some hope on his availability for Sunday but the Niners need to be ready for his absence just anyway.Who Will Step Up Without Mitchell?That leaves Kyle Shanahan with a big question to answer: Who's going to fill in for Mitchell?The Niners' offense is pedestrian at best without the running game but having George Kittle back to full strength could make things easier for Garoppolo.Deebo Samuel has rushed for a couple of touchdowns this season but he's clearly more impactful at wide receiver.That, plus the Niners' never-ending injury issues at RB leave Jeff Wilson Jr. (229 rushes for 999 yards in 4 years with the team) as the only reliable option to lead the way if Mitchell is unable to go.Garoppolo Continues To Be UnimpressiveThe 49ers will need to rely on Jimmy Garoppolo more often this Sunday, which hasn't historically worked in their favor.Garoppolo continues to be a game-manager at best, throwing for 1,936 yards with 10 touchdowns and 5 interceptions over 8 games this season.With Mitchell out, the Niners will need him to be more than just a hand-off, check-down specialist, and actually beat a defense that's getting better every week.This could be the perfect opportunity for him to prove that he's got what it takes to lead this franchise going forward, as first-round pick Trey Lance continues to wait for another chance to take his job.