Jay Ratliff gets some morning work in

OXNARD, Calif. -- In a sign that he could be close to a return, Cowboys defensive tackle Jay Ratliff participated with the first-team defense during a Tuesday morning teaching session.

Ratliff hasn't practiced this summer because he's still recovering from a hamstring injury and rehabbing from sports hernia surgery. Ratliff, who didn't wear a jersey, hasn't been cleared to practice yet by the Cowboys' medical staff but worked half-speed with the defense Tuesday.

In Ratliff's absence during afternoon practices, the Cowboys have used Jason Hatcher and Sean Lissemore at defensive tackle.

Ratliff isn't expected to fully practice this week until the Cowboys break camp Friday.

Cowboys officials believe Ratliff will return in time for the first game of the 2013 regular season and might even play in one of the final two preseason games at AT&T Stadium. Coach Jason Garrett said it's not a requirement for a veteran player coming off injury to practice before participating in a game.