He played junior hockey for the Spokane Chiefs from 2003 to 2007. The New Jersey Devils picked him 170th overall in the 2005 NHL Entry Draft. He won the bronze medal with the United States team at the 2007 World Junior Championship.
Zimmerman turned pro full-time with the Lowell Devils in 2007-08 (he had played some minor pro in the previous two seasons). Just before the start of the 2008-09 season, he was traded to the Phoenix Coyotes for Kevin Cormier.