Jacobs (ankle) didn't practice Thursday, Adam H. Beasley of the Miami Herald reports.
Jacobs was also listed as a non-participant in Wednesday's session. With Adam Hill of the Las Vegas Review-Journal having previously relayed that coach Jon Gruden considered the running back "very questionable" for Sunday's game against the Dolphins, it looks as though Kenyan Drake and Peyton Barber are trending toward continuing to share the Raiders' backfield duties this weekend.