The waiting period was waived for ten players deemed exceptionally notable; Dit Clapper (1947), Maurice Richard (1961), Ted Lindsay (1966), Red Kelly (1969), Terry Sawchuk (1971), Jean Béliveau (1972), Gordie Howe (1972), Bobby Orr (1979), Mario Lemieux (1997), and Wayne Gretzky (1999). Following Gretzky's induction, the Board of Directors determined that the waiting period would no longer be waived for any player except under "certain humanitarian circumstances". Three Hall of Fame members came out of retirement after their induction and resumed a career in the National League: Gordie Howe, Guy Lafleur and Mario Lemieux. Chris Pronger was inducted in 2015 while still technically an active player; in his case, he had signed a contract with the Philadelphia Flyers that was not due to expire until after the 2016–17 season. The Hall of Fame amended its by-laws by introducing the "three-year waiting period", which made Pronger eligible for induction because he had not played since 2011.