The offensive lineman from Notre Dame signed a four-year deal worth about $9 million, with a $4.8 million signing bonus. As with all contracts for first-round picks, there is a club option for a fifth year.
Martin, who went No. 16 overall, is the third offensive lineman taken in the first round by Dallas in the past four drafts. He has been working as the starting right guard in offseason practices and figures to be in the lineup alongside center Travis Frederick, the first-round pick at No. 31 a year ago.
The Cowboys are likely to have four of five starters on the line at 25 or younger. Tyron Smith, the top pick in 2011, is the left tackle. Ron Leary, an undrafted free agent two years ago, is at left guard. The exception is 30-year-old Doug Free at right tackle.
Dallas traded up to get Lawrence with the 34th overall pick out of Boise State and is hoping he can replace franchise sacks leader DeMarcus Ware, who signed with Denver a day after he was released in March.
The Cowboys open their mandatory three-day minicamp Tuesday.
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