Complex sentence: Nebraska was part of the MUSL game "Wild Card" when it began in 1998; it was replaced in May 1999 with the current version of the game, Wild Card 2; simultaneously, Nebraska pulled out.
Split into simpler sentences: Nebraska was part of the MUSL game "Wild Card" when it began in 1998. The game's format changed in May 1999, becoming Wild Card 2; simultaneously, Nebraska pulled out.