Hambrick took over the starting role as running back for the Cowboys last season after the club released Emmitt Smith, the NFL's all-time rushing leader. Now, they will be teammates again in Arizona.
Coach Dennis Green has already named Smith his starter for the 2004 season. The Cardinals lost running back Marcel Shipp for at least two months in early August due to a dislocated left ankle.
Hambrick, 27, rushed for 972 yards and five touchdowns last season. He was released in May. He then signed with the Raiders, but became expendable due to the Raiders' crowded backfield that includes Tyrone Wheatley, Justin Fargas and Zack Crockett.
Zellner also broke in with the Cowboys, playing for the Dallas from 1999-2002. He spent the 2004 season with the Washington Redskins.