Martin joins Jonathan Stupar as the only other tight end on the active roster. The Bills will be without projected starter Shawn Nelson, who opens the season serving an NFL-imposed four-game suspension for violating the league's substance abuse policy.
Buffalo lost three tight ends to injuries this summer, including former starter Derek Schouman who was waived/injured Saturday after hurting his knee two weeks ago.
To make room for Martin, the Bills released tight end J.P. Foschi, a six-year NFL journeyman who was signed as an injury-replacement two weeks ago.
Martin missed last season with a knee injury after playing the previous two years with Miami. He spent his first six NFL seasons with Green Bay, and has 152 catches for 1,519 yards and 14 touchdowns in 101 career games, including 43 starts.
Urbik, a 2009 third-round draft pick out of Wisconsin, was inactive for all 16 games with the Steelers last season. He was released by Pittsburgh on Saturday.
Buffalo also signed four players to its practice squad: running backs Joique Bell and Rodney Ferguson, receiver Naaman Roosevelt and tackle Jason Watkins. All four return after being cut by the team a day earlier.
Copyright 2010 by The Associated Press