With his first swing on No. 15 still under scrutiny, Kevin Na has moved back into a first-place tie with Nick Watney, who is in the clubhouse at 17 under. Na, who hasn’t had a bogey since the second hole, is 5 under for the day following his two-putt birdie on the par-5 16th at TPC Summerlin. Playing in the final group with Jhonattan Vegas (-14) and Charlie Wi (-12), Na looks to be the only player on the course that could reach 18-under (or better) today. The shot in question for Na came on the teebox of the drivable par-4 15th. Na addressed his shot and took a full backswing and follow through. On the downswing, however, something didn’t feel right to Na and he pulled up, apparently missing the ball intentionally as he swung through. PGA TOUR rules officials on site have reviewed the swing but have not made a statement yet, possibly waiting for an opportunity to speak with Na prior to making a ruling -- if there is a ruling to make. As it stands, Na is at 17 under with two holes to play.