Why is the MLB All-Star game in a National League park two years in a row?

It’s supposed to alternate American league, National league ballpark from year to year and last year it was at PNC Park in Pittsburgh where the Pirates of the NL Central Division play. This breaks the pattern. http://mlb.mlb.com/mlb/history/all_star.jsp

Because NY swapped with SF. That’s because next year is the final season the Yankees will play at the old Yankee Stadium. The new Yankee Stadium will be completed in time for the 2009 season.