The Habs knew that Esposito was a good-great goalie but they already had Worsley, Vachon and Dryden in the organization/system. Unfortunately, couldn't keep them all.
"Esposito played thirteen regular-season games, due to both
Gump Worsley and Vachon being injured. However, Esposito returned to the
minor leagues when they both returned from their injuries. Worsley was injured again during the playoffs, so Esposito was called again. He served as backup to Vachon, dressing for all four games in the
Finals as Montreal won the
Stanley Cup, with Esposito having his name engraved on there as a winning member.
As the Canadiens club was deep in goaltenders at that time, with Worsley, Vachon, and other prospects in the SYSTEM, Esposito was left unprotected by the Canadiens in 1969."
Tony Esposito - Wikipedia