The San Francisco 49ers have been without All-Pro left tackle Trent Williams for the last five games, and the future Hall of Famer will also miss the final two.

Niners head coach Kyle Shanahan confirmed in his Monday conference call with local media that the 11-time Pro Bowler will not feature against the Detroit Lions or the Arizona Cardinals because of the ankle injury that has kept him out since the Week 11 loss to the Seattle Seahawks.

Jaylon Moore has filled in for Williams during that period but, after leaving Sunday's loss to the Miami Dolphins with a quad injury, he will also miss the last two games, as will left guard Aaron Banks because of an MCL injury.

Spencer Burford took over for Moore against the Dolphins, playing a position he occupied in college before moving to guard in the pros, but he is day-to-day with a calf injury. 

As such, the 49ers' offensive line, specifically the left side that has historically been excellent with everyone healthy, is in dire straits.

Nick Zakelj will likely fill the void at left guard in Banks' absence, while the hope will be that Burford will recover in time to step in for Moore.

However, if Burford is not healthy enough to face the Lions, then Austen Pleasants, signed by the Niners just last week, will be the frontrunner to play one of the most important positions on the offense.

Williams being shut down for the year is no surprise with the 49ers now out of the playoff hunt, but the dire situation in which they now find themselves in the trenches is the perfect illustration of the remarkable injury adversity that has played a huge role in derailing their NFC title defense.

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