Pro Football Talk is reporting Patrick Willis suffered a sprained toe on Monday, and is seeking a second opinion. Willis had his toe x-ray'd on Monday, and then reportedly underwent an MRI on Tuesday. He is seeking a second opinion from the same doctor who is working with Cincinnati Bengals wide receiver A.J. Green. PFT is also reporting it is "unlikely" Willis plays Sunday against the Denver Broncos.
Tramaine Brock also suffered a sprained toe, and it has since been described by some as turf toe. Brock suffered the injury in Week 1, and is not expected back until the 49ers get through their Week 8 bye. This does not mean that Willis is dealing with the same severity. A turf toe type of injury can vary in degrees. Brock is dealing with a tougher one, but we'll keep our fingers crossed that Willis ends up with a quicker recovery time.
We won't really know anything for certain until we see practice reports, but odds are good it won't be happening this week. Chris Borland will likely take all the practice snaps next to Michael Wilhoite, and start on Sunday against the Broncos. Where it then gets interesting is how the 49ers approach that second inside linebacker role. The 49ers could very well decide to roll out more dime defense than they usually do, thus removing Borland or Wilhoite from the equation.
The 49ers run dime during games on occasion, but the most extensive example of it I remember was Week 1 of the 2012 season. That was Perrish Cox's first regular season game with the 49ers, and he ended up playing 51 of 68 defensive snaps as the dime back. We don't know Jimmie Ward's status yet, but with Dontae Johnson and Chris Cook also available at cornerback, I would not be surprised to see a lot more defensive backs on the field this Sunday.