Tony Romo wasn’t on the practice field as the Cowboys began work Monday. The quarterback took three sacks and was hit another couple of times during Saturday’s game in Miami, but he played the entire first half.The Cowboys have been cautious with Romo’s work during the preseason by not practicing him three days in a row. He skipped the preseason opener against San Diego and played 16 plays, including two penalty plays, against the Ravens. He was on the field for 32 plays against the Dolphins in his final tune-up before the season opener.Romo had back surgery to repair a herniated disk on Dec. 27.The Cowboys also were missing running back Joseph Randle (oblique) and defensive end George Selvie (shoulder), and receiver Dwayne Harris (hip/ankle) returned inside after some early on-field rehab work. All three were injured during Saturday’s game.While defensive tackle Henry Melton (groin) and cornerback Morris Claiborne (shoulder) were back taking first-team snaps in practice, the Cowboys were without 11 defensive players counting linebacker DeVonte Holloman (neck), safety Matt Johnson (hamstring/back), defesnive end Ben Gardner (shoulder), defensive tackle Amobi Okoye (personal health issues), defensive end DeMarcus Lawrence (foot) and defensive end Anthony Spencer (knee).Cornerback B.W. Webb (hip), safety Jakar Hamilton (hamstring), cornerback Johnny Thomas and defensive tackle Terrell McClain (high ankle) were not practicing. Offensive tackle Darrion Weems (shoulder) remains out, too.Tight end Jordan Najvar tore his Achilles’ during Saturday’s game.