The Dolphins signed guard Jeff Braun and waived/injured guard Brian Thomas on Saturday. Braun a 6-4 309-pound undrafted rookie from West Virginia who wasn’t invited to the NFL Scouting Combine was signed by Baltimore on May 4 and cut five days later. He has strength. He bench-pressed 225 pounds 29 times at West Virginia’s Pro Day. But Braun admitted the knock on him is athleticism and that could be a problem in the Dolphins’ zone blocking scheme. More and more the offensive linemen are showing agility and athleticism in practice both in drills and in plays in which guards are pulling or using their feet on screen passes.