The San Francisco 49ers have signed offensive lineman Charlie Heck to a one-year deal and placed offensive lineman Jaylon Moore on the Injured

The 49ers also won’t have left guard Aaron Banks and left tackle Jaylon Moore the last two games, Shanahan said. Banks has a medial collateral ligament injury in his knee and Moore has a quad strain. Guard Spencer Burford (calf) underwent an MRI on Monday to determine the severity of his injury.

The 49ers finished the Miami game with Spencer Buford, the No. 3 tackle, replacing Moore and Nick Zakelj filling in for Banks. And Burford is no sure thing to face Detroit when the 49ers host the Lions in Week 17 on Monday night.

Trent Williams did well to secure strong terms via a reworking completed just days before the season. The perennial All-Pro tackle will not be back to close out Year 1 of this revised agreement.