The coach still needs to field a team on Sunday, and there are concerns about avoiding rust heading into the postseason.
"No one's set right now," Shanahan stated on Monday afternoon when questioned about the plan for the Week 18 contest and how many starters might be sidelined. "I'm still discussing that with coaches and stuff, and just trying to figure it all out, what's best for us. And I'll probably discuss it with those players also, but not as many as you would think. It's really a hard thing to do, and it's not always the best thing to do, too.
"So we're going to take everything into account, but it's still something we're going to continue talking about throughout this day and tomorrow."
Shanahan hasn't decided whether quarterback Brock Purdy will start against the Rams or if Sam Darnold will get most of the snaps.
Regarding his philosophy on avoiding rustiness when not playing in the Wild Card Round of the playoffs, Shanahan stated, "I think it can be tough, but it's not just playing. It's how much you practice and everything, too. You've got to make sure that you prepare for games by practicing. And we got a game this week on Sunday.
"When you give guys the game off, practice changes, too, and that can end up hurting guys a lot, and you end up just developing bad habits. I've seen it cost a lot of teams. And it does give some guys a chance to get healthy, but when you do that, and you sit people, then ... other people got to double up and do a lot more because you only get two guys off a practice squad, also. If you want to get more than two off [the] practice squad, we've got to cut people on our roster, and then we don't get those guys just to get those [practice squad] guys up.
"So it always can end up hurting. You rest players, and that sometimes gets more players injured. So, all that stuff, you've got to balance out, and that's why there's not a clear-cut decision on anything. You've got to look in each individual, in each situation, and play it out as the week goes."