Alex Smith completed 18 of 19 passes for the San Francisco 49ers against Arizona on Monday night.

Or was it 19 of 20 passes? How about 20 of 21?

The answers could depend upon two plays, not just the one San Francisco hopes the NFL changes from a running play to a forward pass.

Why would anyone care? Smith needed 20 pass attempts to qualify for a single-game NFL record in completion percentage.

Coach Jim Harbaugh contends a play first ruled to be a backward pass to Michael Crabtree was actually a forward pass.

That might not be the only play to consider.

The official play-by-play shows a penalty for defensive pass interference wiping out an apparent completed pass to 49ers receiver Mario Manningham during the 49ers' opening drive. It is unclear, however, whether the 49ers accepted the penalty. The flag was thrown on a second-and-4 play, so the 49ers would have gained nothing by accepting the penalty.

If the 49ers did not accept the penalty, the league could conceivably change the play from 7-yard penalty to 7-yard completed pass.

The NFL made a similar change in Week 2 last season.

I'll update as we learn more.