Cowboys' run D needs to tighten up

IRVING, Texas -- Let’s have some fun with numbers, even if there is no true comparison: Having allowed 503 rushing yards in the first three preseason games, that would translate to 2,683 yards in a 16-game regular season for the Dallas Cowboys' defense.

I realize it’s only the preseason and the units are being mixed and matched in part because of injury, but the run defense has not been an issue solely in games. It was an issue almost every day in Oxnard, California, when it was Cowboys against Cowboys, as coach Jason Garrett likes to say.

There was one practice in which running backs DeMarco Murray and Lance Dunbar had roughly five runs in which they were not touched until they were 10 yards down the field.

You could look at that two ways: the Cowboys have a dominant offensive line or they have a poor front seven. Both might be true.

The Miami Dolphins ran for 200 yards on 35 carries against the Cowboys.

"I think it’s a probably a combination of things based on who is in the game," Garrett said of the run defense. "I think gap discipline and making sure your run fits are right, that's been an issue at different times throughout the preseason. Getting off blocks, tackling. Those things we have to get better at.

"Hopefully our defense grows in those areas. I think we have shown improvement from the start of training camp until now. Individual guys have gotten better. We have to get better as a team. Obviously you can’t allow a team to run the football and control the game like that."

Defensive linemen Henry Melton and Terrell McClain have yet to play a preseason snap. The linebacker trio is unsettled as well. The Cowboys have not done much work by bringing a safety down in the box to help the run defense.

The Cowboys open the season against the San Francisco 49ers, who feature running back Frank Gore and a running threat at quarterback in Colin Kaepernick. They will have four division games against Philadelphia Eagles running back LeSean McCoy and Washington Redskins running back Alfred Morris. Mark Ingram of the New Orleans Saints and Matt Forte of the Chicago Bears ran for 100 yards against the Cowboys last season and are on the schedule this season. Running back Marshawn Lynch of the Seattle Seahawks is also on the schedule.

"Coach tells us to see a little, see a lot, meaning we just do our job, play our gap and everything else will just come," defensive end Tyrone Crawford said. "We’ve got one gap to play. It’s one game football. We’ve got one job to do, if we do that job and trust in our defense and trust in the call, everything will work out."