Kammala jumla mai zuwa: Bayan ya zauna a Goodeve, Saskatchewan, da Melville, Saskatchewan, a lokacin yaro, McLellan ya fara aikinsa tare da Saskatoon Blades na Yammacin Hockey League (WHL) daga 1983 zuwa 1987. A cikin
1986 NHL Entry Draft, New York Islanders ne suka zaba shi a zagaye na biyar. Ya buga jimillar wasanni biyar a matakin NHL, yana ciyar da mafi yawan yanayi biyu tare da reshen Islanders na American Hockey League (AHL), Springfield Indians. Koyaya, raunin da ya faru a kafada wanda ya koma kwanakin wasan hockey na matasa ya kawo karshen aikin McLellan na Arewacin Amurka bayan kakar 1988/89. Ya zira kwallaye na NHL kawai a wasan farko a ranar 28 ga Disamba, 1987 a cikin rashin nasara 6-4 ga New Jersey Devils.