San Francisco head coach Kyle Shanahan said Monday that Guerendo has been diagnosed with a foot sprain and will be considered day-to-day heading into Thursday's game against the Rams, Nick Wagoner of ESPN.com reports.
Shanahan said that the team will "evaluate [Guerendo] over the next few days, to see if he'll have a shot" to suit up for Thursday Night Football, per Adam Schefter of ESPN. Before exiting Sunday's 38-13 win over the Bears in the fourth quarter, Guerendo compiled 128 yards from scrimmage and two touchdowns while operating as San Francisco's lead backfield option. In the event that Guerendo isn't able to play Thursday, Patrick Taylor will be the next man up at running back, with Christian McCaffrey (knee), Jordan Mason (ankle) and Elijah Mitchell (hamstring) all on IR. The 49ers also have Ke'Shawn Vaughn and Israel Abanikanda available behind Taylor.