Rubuta ci gaba don wannan sakin layi - Kodayake ya buga wasan All-Star na biyu a 1990, yawan aikin Mullen ya ragu da maki 41, zuwa 69, kuma ya kasa zira kwallaye aƙalla 40 a karon 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 ranar da aka zaɓa
musayar a ranar 16 ga Yuni, 1990, a musayar zagaye na biyu na zabin Pittsburgh.