With production of “Spider-Man 4” delayed, Paramount and Marvel Entertainment have pushed up the release of “Thor” by two weeks to May 6, 2011.

Thor” was set to have opened May 20, 2011. No sooner did Par make its move than did Disney grab the May 20 slot for “Pirates of the Caribbean: On Stranger Tides.” The fourth installment in the “Pirates” franchise did not previously have a release date.

Strategic shuffling came one day after Sony confirmed that lensing of “Spider-Man 4” has been delayed because of script issues and that it may not make the May 6 deadline.

Sony said it wasn’t abandoning the date, a highly-coveted frame since it is the first weekend of summer. Studio said it is still hoping to complete the film in time.

However, Paramount decided to act aggressively and not wait for the outcome, in case another studio acted first and put one of their films there.

Paramount didn’t comment on its decision, but it didn’t come as a surprise to rival studios, since “Thor” is the first movie skedded for release after “Spider-Man 4.”

Two of the three “Spider-Man” pictures have opened the first weekend of summer; the third, over the Memorial Day holiday.

Should “Spider-Man 4” stick to the May 6 release, it’s likely that “Thor” would move.