In a statement, Roberson thanked his coaches for "taking a chance" on him and said he'll look for a new home with three years of eligibility remaining.
A handful of Penn State women's volleyball standouts are reportedly searching for new homes.
Diaz has 24 years of collegiate coaching experience and was most recently Miami's head coach.
Saint's will be replaced by Philadelphia roasting company Elixr Coffee.
Officials said crew members climbed to the building's roof and found only one of the Computer Building's air ventilation units was functioning fully.
"I could not pass up the chance to be with this family and play the game I love again."