Memorial Stadium also served as the university's track and field venue, and was an occasional back-up venue for professional football and soccer. In 1969, the NFL's Minnesota Vikings played a regular season game on October 5 against the Green Bay Packers at Memorial Stadium. It was due to a conflict with a Minnesota Twins playoff game at Metropolitan Stadium, game three of the 1969 American League Championship Series the following day. The Vikings also played a pre-season game at Memorial in 1971, its second season with artificial turf. The artificial Tartan Turf was removed after seven seasons and returned to natural grass in 1977.