Kammala jumla mai zuwa: Ko da yake ya taka leda a karo na biyu na All-Star Game a shekarar 1990, yawan aikin Mullen ya ragu da maki 41, zuwa 69, kuma ya kasa zira kwallaye akalla 40 a karo na farko a cikin yanayi shida. Damuwa game da shekarunsa, Flames sun zabi suyi musayar Mullen mai shekaru 33 bayan kakar wasa. An tura shi zuwa Pittsburgh Penguins a
a ranar 16 ga Yuni, 1990, a musayar zabin zagaye na biyu na Pittsburgh.