Are you referring to Dustin Brown or Lucic? Those are the only 2 players I can think of.
Brown and Lucic were never integral in Boston and LA cup runs.
For the Kings, it was Doughty, Quick, Kopitar, Carter, Gaborik (2nd cup)
For the Bruins it was Bergeron, Krejci, Chara, Rask/Thomas. At least imo, Virtanen types are not critical to success