Dallas Cowboys six-time All-Pro guard and team captain Zack Martin is considering not reporting to training camp because of his unhappiness with his contract and the team's lack of interest in restructuring it, sources told ESPN's Adam Schefter.

Martin said he is "woefully underpaid relative to the market," a source said.

Martin is scheduled to make about $7 million less this season than the NFL's top-paid guards. Chris Lindstrom of the Falcons and Quenton Nelson of the Colts are at the top of that list this season at an average of $20 million.