The site on which the mall was built had been occupied by Metropolitan Stadium between 1956 and 1981. The structure was replaced by the Hubert H. Humphrey MetroDome (which was built at another location).
Photo from Wikipedia / "Wahkeenah"
A commemorative plaque marks the location of home plate, in the "Old Met" stadium. This is found in the northwest corner of today's Nickelodeon Universe indoor theme park.
Photo from Wikipedia / "Yassie"