For its 2015 season, the league consisted of 12 teams, all from the United States; however, upon the completion of the regular season, the league announced that the two teams it had assumed operation of during the season would cease all operations effective immediately; a regular season game slated between the two had previously been canceled and declared a tie. Subsequently, one of the remaining teams, the Spokane Shock, severed its ties with the league to join the competing IFL. The AFL is divided into two conferences  –  the American Conference and National Conference. Starting 2016, each conference will have only four teams as the champion San Jose SaberCats announced in November 2015 that they were ceasing activity for "reasons not associated with League operations."
Try to answer this question if possible (otherwise reply "unanswerable"): What team left the AFL after the 2015 season to join another league?
Spokane Shock