Mullens completed eight of 11 pass attempts for 84 yards in Saturday's 27-17 preseason win over the Chiefs.
Mullens was the first and only quarterback to relieve starter Jimmy Garoppolo in Saturday's dress rehearsal. This all but confirms that the 24-year-old will be the primary backup to begin the season. Coach Kyle Shanahan said he plans to keep both Mullens and C.J. Beathard on the 53-man roster, according to Cam Inman of The Mercury News. While that may simply be a ploy to keep both signal callers' trade value in tact, Mullens at least seems like a strong bet to stick around.