OXNARD, Calif. -- A daily review of the hot topics coming out of Dallas Cowboys training camp:

• With Jason Garrett wanting to work the players even more slowly than the collective bargaining agreement allows, the offense did not work against the defense on Thursday. The CBA requires teams to not work in pads until the third day of training camp. Garrett has looked at ways to mitigate injury concerns, so he kept the offense and defense separate. The only time the sides had 11-on-11 drills came in the morning walkthrough as well as the early portion of the afternoon workout.

• Defensive end Anthony Spencer joked he would practice on Friday but acknowledged the possibility he will open the season on the physically unable to perform list. The Cowboys placed Spencer on the active/PUP list on Thursday, which gives them the possibility to put him on reserve/PUP later this summer, which would knock him out for the first six games of the season. Spencer had microfracture surgery last season after suffering a knee injury in last summer's training camp. He said he had a good day of rehab on Thursday but he has yet to be able to start cutting while running. He said he will continue to run straight ahead and push and pull a sled in his rehab.

• Justin Durant took the first-team snaps on defense at middle linebacker, just as he did for most of the organized team activities and minicamp after Sean Lee suffered a season-ending knee injury in May. For further proof that Durant is the leader to be Lee's replacement, he spent time with linebackers coach Matt Eberflus going over checks and calls during the special teams' portion of the workout. He was the only linebacker not involved in the special teams' drills.

• With Ronald Leary on the physically unable to perform list because of a hamstring strain he suffered in Monday's conditioning run at Valley Ranch, Mackenzy Bernadeau took the first-team snaps on Thursday and most of the second-team work. Bernadeau has started 27 games the last two seasons at right guard, but with the Cowboys drafting Zack Martin in the first round, he now has to compete with Leary. Bernadeau also took some backup center snaps. He will be the backup to Travis Frederick at center on gameday.

• During the spring, the Cowboys started to operate their practices with loud music playing. They will continue that during training camp. The music cuts off after the play and does not resume until the offense breaks the huddle.