The 49ers can bring two players back from injured reserve, and Shanahan didn't dismiss the possibility of Taylor and Hurd still returning. He did, however, sound less optimistic about the chances of that happening.
"Not as much (chance for an earlier return) as there was earlier," Shanahan told reporters on Wednesday. "They both had chances to come back earlier. Both of them have had setbacks, which had to start a couple of things over. We haven't ruled them out, but I'm still hoping for it, but it's not something we can for sure count on."
The setbacks may have prompted the 49ers to be more aggressive in the trade market and push to acquire Sanders from the Denver Broncos.
"I was a lot more optimistic earlier in the year," Shanahan added, "but there's been a few setbacks that we can't guarantee that, and it's a risky thing when you're dealing with injuries and stuff. It's a risky thing to do when you've got to make a decision here by next Tuesday (the trade deadline) where we're going to go."
The plan is to have Joe Staley practice on Wednesday, but it will be limited. The 49ers' starting left tackle suffered a fractured fibula during Week 2, and Shanahan says there is still an "outside chance" he plays on Sunday against the Carolina Panthers.
Wide receiver Deebo Samuel (groin) is also expected to be limited on Wednesday. He did not play during the 49ers' Week 7 win over the Washington Redskins. Defensive end Dee Ford, defensive tackle D.J. Jones, tight end George Kittle, and running back Raheem Mostert will also be limited.