WR Jimmy Smith who dressed for seven games but did not catch a pass. Smith was a second round choice of the Cowboys in the 1992 NFL draft and spent two injury and illness plagued seasons with them before being let go prior to the 1994 season. He spent 1994 out of football and was signed by the expansion Jacksonville Jaguars prior to the 1995 season. He ended his career with 862 receptions for 12,287 yards and 67 receiving TDs.
I don't know who is wearing it now, if anyone, but Michael Irvin wore it back in the Troy Aikman era. The Cowboys don't officially retire jersey numbers like many other teams do, but you're not going to see current players wearing numbers like #12 (Roger Staubach) or #74 (Bob Lilly), and probably not #88 either.
Edit: Dez Bryant (OK State) now wears the #88 jersey for the Dallas Cowboys.
Number 82 on the Dallas Cowboys is Jason Witten. He is a Tight End.
Defensive tackle Leon Lett wore #78 for the Cowboys between 1991-2000.
TE Cleo Simmons.
Ed too tall Jones
Wide receiver Roy E. Williams wore the number for the Dallas Cowboys from 2008 to 2010.
Punter Mike Saxon wore No. 4 for the Dallas Cowboys from 1985 to 1992. Placekicker Shaun Suisham wore the number during his first tour of duty with the Cowboys in 2005 and 2006.
Billy Joe Dupree wore #89 jersey in 1978
Linebacker Bruce Carter wears the number for the 2011 Dallas Cowboys.
Roger Staubach wore #12 during his career with the Cowboys.
Running back Marion Barber III wore No. 24 for the Dallas Cowboys from 2005 to 2010.
Don Meredith wore #17 for the Cowboys.
Bob Lilly wore # 74.
Sanders wore No. 21 during his years with the Atlanta Falcons (1989-1993), the San Francisco 49ers (1994), the Dallas Cowboys (1995-1999) and the Washington Redskins (2000). He wore No. 37 during his two seasons with the Baltimore Ravens (2004-2005).
Quincy Carter wore No. 17.