The San Francisco 49ers’ offensive line is struggling, and those struggles aren’t going to get any easier after a trio of injuries cropped up in the team’s Week 16 loss to the Miami Dolphins.

Head coach Kyle Shanahan on Monday in a conference call with reporters said reserve offensive tackle Jaylon Moore and left guard Aaron Banks both suffered season-ending injuries Sunday.

Moore went down with a quad injury in the third quarter while pass blocking. Banks left the game early in the fourth quarter after he was rolled up on during a run up the middle by running back Patrick Taylor. Shanahan said he has an MCL injury that will cost him the final two games.

Those injuries are the most significant for now, but reserve OL Spencer Burford is also working through a calf injury. As of Monday afternoon Shanahan didn’t have an update on Burford whose MRI results hadn’t come back.

Even if Burford isn’t out, Moore going down means the 49ers will be on their third-string left tackle. It doesn’t get any better at left guard where backup Ben Bartch is already out for the year with a high ankle sprain. At minimum the 49ers will be on their third-string left guard.

However, Burford is their third-string left guard and their third-string left tackle. If he’s in, he’ll likely play left tackle which means San Francisco will be down to their fourth-string left guard for the final two games. If Burford can’t go because of the calf injury, it’ll be a fifth-string left guard and fourth-string left tackle.

Shanahan also indicated linebacker Dre Greenlaw could be done for the season after experiencing soreness in his right calf. Greenlaw tore his left Achilles in the Super Bowl in February and made his season debut in Week 15. MRI results also hadn’t returned for him, but Shanahan said his gut told him Greenlaw would likely be shut down for the year. That decision wouldn’t come until after the head coach had gotten a chance to talk with the pending free agent.

It looks for now like second-year LB Dee Winters would be Greenlaw’s replacement, but Winters is day-to-day with a chest injury after Sunday’s game.

Safety Ji’Ayir Brown is also day-to-day with an ankle issue.