Complex sentence: The men's hockey team had used the venue for home games prior to them becoming the newest member of Hockey East in 2014, but have since moved to the XL Center in Hartford, Connecticut as their primary arena.
Split into simpler sentences: The men's hockey team had used the venue for home games prior to them becoming the newest member of Hockey East in 2014. But have since moved to the XL Center in Hartford, Connecticut as their primary arena.