Niners linebackers Patrick Willis and Takeo Spikes will play, although both have broken right arms, a source with knowledge of the situation told NFL.com senior writer Steve Wyche. Both were listed as questionable.
NFL Network insider Alex Flanagan reported that Willis had surgery on his hand Monday to have a pin inserted. He will wear a cast for which he was fitted Wednesday. Spikes also will play with a cast, and both players are expected to have their arms reinforced with padding and tape.
With Willis and Spikes ailing, linebacker Navarro Bowman is scheduled to receive more playing time, NFL Network insider Jason La Canfora reported, citing a team source.
The Chargers signed linebackers Darry Beckwith and Brandon Lang from the practice squad to the active roster in time for the game -- both will be needed on special teams -- and waived running back Curtis Brinkley and placed safety Pat Watkins on injured reserve with a knee injury to make room for them.
The Associated Press contributed to this report.