Willie Parker among bubble boys

The Ravens' Troy Smith, left, and the Redskins' Willie Parker appear to be on shaky ground. Getty Images/AP Photo

Arizona Cardinals quarterback Matt Leinart went from early-line starter to on the bubble because of his inability to persuade coach Ken Whisenhunt he can run the team's offense at a playoff level.

Now, he's going to be traded or possibly cut. Between now and 6 p.m. ET Saturday afternoon, more than 700 players have to be moved off rosters as teams trim from 75 to 53 players. Expect plenty of little trades and lots of waiver claims. Teams hoping to slide young offensive linemen, wide receivers and cornerbacks through the waivers with hopes of getting them on practice squads will have problems. Those positions are in demand, particularly for young, low-paid talent.

Many interesting names are on the bubble as teams make their decisions.

Wide receivers: Could the Seahawks trade wide receiver T.J. Houshmandzadeh even though he has a $7 million guarantee in his contract? Probably not, but his name projects to the bubble even though odds favor him staying. The Cowboys have Sam Hurd on the bubble and might see if they can get trade value for him. Dallas dealt Patrick Crayton to San Diego on Friday. Saints receiver Adrian Arrington has had a great training camp, but he's on the bubble if the Saints stay with five receivers. The Steelers signed Arnaz Battle as a backup receiver and special-teams player, but draft choices Emmanuel Sanders and Antonio Brown did so well, Battle is on the bubble. Former first-round pick Michael Clayton is on the bubble in Tampa Bay because of the good young receivers added to the team in the past two years.

Running backs: The Redskins must decide between Larry Johnson and Willie Parker for the final running back spot, but Parker is clearly on the bubble. Willis McGahee of the Ravens and Marshawn Lynch of the Bills should make their teams, but the right trade offer could put either on the move. The Bears could give up on tiny running back Garrett Wolfe, a third-round pick in 2007. Laurence Maroney is on the bubble after an inactive preseason but could survive if the Patriots keep five backs. The Seahawks have halfback Julius Jones on the bubble after two unproductive years.

Quarterbacks: Leinart heads the list. Charlie Whitehurst probably saved his No. 2 job in Seattle with Thursday night's performance in Oakland, but nothing is certain with the Seahawks' roster. Troy Smith is a nice luxury for the Ravens, but if they need an extra roster spot for a cornerback, the Ravens could part with Smith, who is third behind Joe Flacco and Marc Bulger. The Raiders have to sort out whether to keep Bruce Gradkowski, Kyle Boller and Colt Brennan as backups. All are on the bubble. Chris Simms of the Titans is on the bubble because the coaching staff likes sixth-rounder Rusty Smith as a third quarterback.

Offensive line: The Packers have excess and are willing to part with either Breno Giacomini or Allen Barbre, two former draft choices. The Seahawks have to decide whether free-agent signings Ben Hamilton and Chester Pitts are healthy enough to be contributors or potential starters. The Cardinals could part ways with guard Reggie Wells or Deuce Lutui after adding guards Alan Faneca and Rex Hadnot. The Jaguars have former third-round choice Vince Manuwai or Uche Nwaneri on the bubble if they want the luxury of keeping Justin Smiley.

Defense: The Browns and Bills are overloaded in the secondary. The Bills are five deep at corner and have Ashton Youboty and Reggie Corner on the bubble. The Browns have upgraded enough at corner that Brandon McDonald is on the bubble. The Broncos traded a 2010 first-round pick for cornerback Alphonso Smith, but the 2009 second-rounder is now on the bubble. The Texans could part ways with high-priced cornerback Jacques Reeves.

John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.