Jacobs (toe/ankle) didn't practice Wednesday, Paul Gutierrez of ESPN.com reports.
Per Adam Hill of the Las Vegas Review-Journal, head coach Jon Gruden previously referred to Jacobs as "very questionable" for Sunday's game against the Dolphins. The running back's absence from practice Wednesday would seem to reinforce his cloudy Week 3 status. If Jacobs is sidelined for a second straight game this weekend, Kenyan Drake and Peyton Barber will continue to share the Raiders' backfield duties.