Complex sentence: A deal for a new Vikings Stadium was in the works, thus quieting relocation talk, but the negotiations fell through, and the situation was further complicated by the collapse of the Metrodome's inflatable roof prior to the end of the 2010 season.
Split into simpler sentences: A deal for a new Vikings Stadium was in the works, thus quieting relocation talks. However, the negotiations have since fallen through, and the situation has been further complicated by the collapse of the Metrodome's inflatable roof prior to the end of the 2010 season.