The Cowboys have expressed interest in free-agent defensive lineman Amobi Okoye according to a source. Team officials have no plans at the moment to bring in any linemen for a workout but the team does have one roster spot available on their 90-man roster. The goal is to fill that spot with a defensive lineman. Okoye played in nine games last season for the Chicago Bears under then-defensive coordinator Rod Marinelli who is now the defensive line coach for the Cowboys. Okoye a 2007 first-round pick by the Houston Texans has 16 career sacks. The Cowboys have lost four defensive linemen to injury in the first three days of training camp. Starting defensive end Anthony Spencer was sent back to Dallas to undergo surgery on his left knee. The recovery time is two to four weeks. Starting defensive tackle Jay Ratliff hasn't practiced yet because of a hamstring strain and his return date is unknown. Backup defensive end Tyrone Crawford suffered a torn Achilles injury the first day of training camp and is lost for the season. Before Tuesday's morning walk-through practice backup defensive tackle Ike Igbinosun was seen wearing a protective boot on his right leg. His status is unknown.