OAKVILLE, Ontario — Brandt Snedeker was on the seventh tee when he noticed something wasn't quite right.
He couldn't find Hunter Mahan's name at the top of the Canadian Open leaderboard.
"I looked at my caddie, and I go, 'What's going on?' " Snedeker said. "He goes, 'I think Hunter had to leave because (his wife) went into labor.' "
His caddie was right.
Mahan, the second-round leader, withdrew Saturday to go to Dallas for the birth of his first child.
"Kind of left the tournament wide open," Snedeker said. "Hunter was going to be hard to catch because he was playing so good. For me to catch him, I knew I was going to have to shoot something really low."
Snedeker had 9-under 63 at rainy Glen Abbey to take the lead after the third round at 14-under 202 overall. He won the Pebble Beach National Pro-Am in February for his fifth PGA Tour victory.
"I know how to handle it, and I know what to expect (today), especially on a golf course like this," Snedeker said. "I'm not too concerned about my number right now. I know what I have to do."
The 2012 FedExCup champion had nine birdies in a bogey-free round, playing the front nine in 6-under 29.
"You always feel like you're exactly one swing away from hitting something off the planet or something like that," Snedeker said. "I felt like I managed my game really well."
Mahan withdrew before he was scheduled to tee off in a round that was delayed 80 minutes because of lightning.
"I received exciting news a short time ago that my wife, Kandi, has gone into labor with our first child," he said in a statement. "Kandi and I are thrilled about the addition to the Mahan family, and we look forward to returning to the RBC Canadian Open in the coming years."
Swedens' David Lingmerth was a stroke back after 65, and Matt Kuchar (64) and Jason Bohn (66) were 12 under.
"The birth of a child is a truly magical, special thing. You may get it once in your lifetime. It just doesn't happen that often," Kuchar said. "Hunter right now is playing some of the best golf in the world. It kind of gives the rest of us a chance with him not in the field."
Dustin Johnson also shot 63, good for a tie for fifth at 11 under with John Merrick (72), Greg Owen (67), Charley Hoffman (67) and Kyle Stanley (66).
CHAMPIONS: Bernhard Langer seized a three-shot lead after the third round of the Senior British Open in Southport, England, mastering Royal Birkdale with superb links play for 4-under 66.
Langer shared the overnight lead with Mark Wiebe but birdied three of his first seven holes to jump in front, finishing at 9-under 201. David Frost shot his third straight 68 to sit alone in second place. Wiebe shot 70 and was in third at 5 under.
Langer's only bogey came on the 14th. He had birdies on 15 and 17 to stay in control.
"That was as good as I can play," said the German veteran, bidding for his second Senior British Open title after winning at Carnoustie in 2010. "My ball-striking was almost perfect, and I played really well, apart from the mistake at the 14th."