Pryor has appeared in three games -- two this season -- in very limited play over his first two NFL seasons. He's attempted just two passes, completing one.
Allen said Friday that usual starting quarterback Carson Palmer hasn't recovered from cracked ribs and a bruised lung suffered in last Sunday's loss to Carolina and was out for Sunday.
Even missing the final game, Palmer passed for 4,018 yards this season, the third time in his career he's reach that figure.
The Raiders are 4-11 on the season. San Diego goes into the final game of 2012 with a 6-9 record. Both trail the Denver Broncos (12-3) in the AFC West.