Isaac Guerendo

Jordan Mason emerged as the workhorse, carrying 13 times for 78 yards (6.0 YPC), including a 28-yard breakaway run. He played 52% of snaps and handled two red zone carries.
Christian McCaffrey contributed 53 yards on seven carries before exiting due to an injury, logging a 25% snap share. McCaffrey was active as a receiver before his injury, catching two of three targets for 14 yards. We might have seen the last of CMC this season with the 49ers falling out of the playoff conversation. He suffered a PCL injury in the contest that may be season-ending
The 49ers have a 9% chance of making the playoffs at 5-7.
Isaac Guerendo was effective in a complementary role, gaining 19 yards on four carries and scoring on a backward pass trick play inside the red zone. He played 23% of the snaps.
Mason looks like he will be back in the starting role rest of the season.
Well, at least that was the idea before the 49ers also placed Mason on IR with a high-ankle sprain.
Empty the clip (or whatever is left) and go for broke on Guerendo. As for deeper formats, add Patrick Taylor who will also likely see some action.

With both Christian McCaffrey and Jordan Mason being placed on injured reserve Monday, 49ers RB Isaac Guerendo is now in line to be the team's lead back.

Fantasy Impact

Guerendo has been an efficient runner so far this season, averaging 5.9 yards per carry. In Kyle Shanahan's offense the rookie RB should be able to put up viable RB2 numbers at minimum, as long as McCaffrey and Mason are both on IR.