The signing of quarterback Seneca Wallace on Thursday could signal a shift in not only the 49ers’ offensive philosophy but the league as a whole.

The 49ers were obviously hoping that traditional drop-back quarterbacks Scott Tolzien and Colt McCoy would gain enough mastery of the 49ers offense to be effective. Since both have below average NFL arm strength and neither of them are considered read-option quarterbacks they both had to rely on anticipation and accuracy. They haven’t showed that so far in the preseason.

It means if Colin Kaepernick gets hurt not only would the read option part of the offense be eliminated but so would Kaepernick’s ability to be an effective drop-back passer. Suddenly the 49ers go from a 12-win team to a 6- or 7-win team.

However if the 49ers can find a quarterback who can also gain yards with his legs as a read-option player they wouldn’t have to eliminate that explosive element to their offense. Hence the signing of the highly-mobile Wallace and the more serious look at seventh-round rookie B.J. Daniels.

With a read-option element now a replacement doesn’t necessarily have to complete 60 percent of his passes and throw for 280 yards a game. Instead he can make up for the loss of passing offense by running and by the tactical advantage of the read option which still has NFL defenses befuddled.