The Jets signed running back Tony Fisher and linebacker Mark Zalewski on Friday. Fisher, who spent last season with St. Louis after four years with Green Bay, should add depth to the Jets' running back corps. Cedric Houston left the team abruptly Thursday for personal reasons, leaving the Jets with just Thomas Jones, Leon Washington and undrafted rookies Danny Ware and Alvin Banks at the position at the start of training camp. Fisher made it in time to participate in the Jets' late practice Friday.