The Cowboys defense was hit with another serious injury on Tuesday. (USATSI)
The Cowboys defense was hit with another serious injury on Tuesday. (USATSI)

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The Dallas Cowboys defense was ranked dead last in the NFL in 2013 and things aren't looking so great for 2014 either. Rookie defensive end DeMarcus Lawrence broke his right foot in practice on Tuesday and is expected to miss at least 8-12 weeks, according to the Fort Worth Star-Telegram

If Lawrence ends up missing 12 weeks, he wouldn't return until Week 8. 

The 34th overall pick in the 2014 NFL Draft, Lawrence went down after doing a drill where he was being blocked by left tackle Tyron Smith. Lawrence clutched his right ankle after being knocked to the ground and was unable to get up. The defensive end ended up being carted off the field. 

Lawrence is the second player since May on the Cowboys defense to go down with a serious injury. The team lost linebacker Sean Lee for the season when he tore his ACL during practice on May 27. Lee was placed on injured reserve in July and won't be returning in 2014. 

The loss will hurt the Cowboys' depth on the defensive line. Part of the reason Dallas took a defensive end so high in the draft was to replace DeMarcus Ware and Jason Hatcher, who both left in free agency.