Taking advantage of calm and clear conditions to attack the fairways and pins, 15 players finished within a shot of the lead and 46 of the 68 players were even par or better on the Crosswater course
-- the tour's longest at 7,533 yards.
The 54-year-old McNulty, from Zimbabwe, has three top-five finishes this year and hasn't missed a cut. He blistered the course with a 16-under 272 last year in the event's first year at Crosswater. In five rounds, he has shot 66, 68, 68, 70 and 67.
"I played nice and steady and had a good front nine to start," McNulty said. "That's what you want when you come back to defend a title."
Wiebe played well after poor results in the Senior British Open, where he finished at 7 over, and the Senior U.S. Open, where he missed the cut. Wiebe, born in Seaside, Ore., birdied five holes on the front nine, including four in a row.
Stadler birdied five holes on the back nine and could have held the lead outright, but he double-bogeyed the 456-yard, par-4 18th.
"I looked at the turn and saw Stads was at 7 under," said Haas, who birdied five of the first 12 holes and just missed birdie putts at 15 and 17. "Then I didn't see a board again until 15 and I saw the lead was five. I thought they just hadn't updated that board yet."
Tournament host Peter Jacobsen withdrew from the field before teeing off because of a hip injury. The Portland native also has battled knee and back injuries and has withdrawn from the tournament in each of his last three years.
Divots: Former Ryder Cup player Des Smyth found out Thursday that 24-year-old son Gregory won the Irish National Lottery, worth about $14 million. Smyth shot a 71. "It's all very surreal," Des Smyth said. "Being so far away from things, it's hard to grasp. We got a call in the hotel at 6:20 a.m. this morning. Usually when you get a call that early, it's not good but he assured us right at the start that it was good news he was about to tell us. I played today but honestly can't remember a single shot I hit. I was thinking about him all day. He'll be well advised for sure. I just hope he takes it." ... Charles Schwab Cup points leader Bernhard Langer birdied the final four holes and was among the eight players one shot off the lead at 4 under.