Tobin signed a one-year deal with the Patriots on Wednesday, Kevin Duffy of MassLive.com reports.
Tobin signed a deal with New England last March but failed to make the 53-man roster. The 28-year-old then signed with San Francisco in mid-September but was later released to make space for linebacker Reuben Foster. Tobin will now likely be the fourth tackle on the team behind Trent Brown, Marcus Cannon and LaAdrian Waddle.