W2W4: Cowboys training camp: Day 15

OXNARD, Calif. -- The Cowboys enter the homestretch of training camp on Monday.

Defensive injuries: The Cowboys lost three defensive players to injuries and one more to a personal matter. Defensive coordinator Monte Kiffin is minus four players: Sean Lissemore, Eric Frampton, Ernie Sims and J.J. Wilcox. The injuries have left the Cowboys thin at the safety position because Frampton (hamstring) and Wilcox (personal matter) missed the team portions of Sunday's practice and second-year safety Matt Johnson (foot) won't practice this week. The defensive line was already missing two players, Anthony Spencer and Jay Ratliff, to injuries and add Lissemore to the mix and the Cowboys are down to 12 linemen on the 90-man roster.

Offensive line getting better: The more snaps Ronald Leary, the left guard, and Mackenzy Bernadeau, right guard, are getting the better the offensive line is becoming. Leary and Bernadeau missed practice time due to injuries early in camp, but each has looked good in the last four training camp practices. The team is still waiting for Brian Waters to make a decision regarding signing with the team. If he doesn't the Cowboys will stick with Leary and Bernadeau as the first-team guards for now.

Armstrong building a case: The Cowboys might keep five wide receivers, but Anthony Armstrong is putting in work to maybe force the team to add a sixth one. Tim Benford and Jared Green are also in the mix for a possible sixth spot, but Armstrong is the leader in the clubhouse because he's running good routes, catching tough passes and doesn't have mental mistakes. He's also doing a good job on special teams, something that the sixth receiver is going to do regardless.

Running backs becoming welterweight champs: Phillip Tanner and Lance Dunbar are not Floyd Mayweather, considered the best fighter, pound-for-pound, in boxing. Yet, in the last couple of practices, Dunbar and Tanner have gotten into scraps. Tanner on Sunday and Dunbar last week. The best position group on the team could be the running back position where Dunbar, No. 2 behind DeMarco Murray and Tanner, No. 3, in front of rookie Joseph Randle, are running to contact and showing great vision. The Cowboys are expected to keep four running backs, but it could drop to three if Tanner struggles on special teams, which he's not. So expect four on the roster.