Deadmarsh would miss most of the 2002–03 NHL season because of a concussion and missed the whole 2003–04 NHL seasonbecause of another concussion. He also did not play the next season because of the 2004–05 NHL lockout. On September 22, 2005, he announced that he was retiring from playing professional ice hockey. On March 20, 2006, Deadmarsh was honoured before a game between the Avalanche and Kings at Staples Center.