The news comes just two days before the Niners were set to kick off the season on Monday Night Football versus the Los Angeles Rams.
Davis is listed as questionable on the 49ers' injury report after not participating in Saturday's practice for non-injury reasons. The team did not confirm the report that the lineman is pondering stepping away again.
Davis, 26, was on the reserve/retired list for all of 2015 after he decided to take a break from football amid concerns about concussions. NFL Network's Mike Garafolo noted that Davis returned in 2016 focused on winning back his starting gig.