ASHBURN The Washington Redskins practiced this morning without the services of cornerback Shawn Springs, safety Chris Horton and running back Rock Cartwright. Springs and Horton missing practice was not surprising. Any time Cartwright misses as much as a drill, it is a surprise.

Cartwright has a rib cartilage injury, one of the more painful injuries to have as a football player.

"I know how that feels," Redskins coach Jim Zorn said. "He just has to get that calmed down."

Springs sat out a second day of practice with a strained Achilles tendon. Horton was sick yesterday and was given another day off.

Free safety Justin Hamilton took part in his first practice of the preseason with the Redskins. Hamilton, a native of Castlewood in southwest Virginia, played at Virginia Tech. He was a seventh-round draft choice of Cleveland in 2006, and had 15 tackles for the Browns that season. Hamilton, 6-3 222, was cut by the Browns last summer and did not play in the league in the 2007 season.

Hamilton was on the Redskins' roster during the off-season, but was cut on May 30. With Springs sidelined and LaRon Landry not likely to play Saturday against Buffalo, the Redskins needed depth at safety. The roster spot for Hamilton opened when Pete Schmitt, a fullback/tight end, decided to leave the team.

"He just hung it up," Zorn said of Schmitt after the morning practice.

Schmitt had been signed on Monday. -- Paul Woody