The 26-year-old Australian, who entered Sunday tied for the lead at 9 under, zoomed out to the lead with birdies on Nos. 2, 6 and 7 before mixing in three bogeys -- two in the last three holes -- to finish with a 1-under 70.
'I'm very disappointed,' Baddeley said after his round, which left him three strokes behind leader Brett Wetterich. 'I felt like I got nothing out of my round in comparison to how well I played.'
Baddeley bogeyed the 16th hole, a 161-yard par 3, when he three-putted from 66 feet. Only a sand save on No. 17 kept him from a more disappointing finish, because he bogeyed No. 18 after putting his second shot into the hazard on the right, then two-putted from 14 feet.
That dropped from a tie for third and a final-round pairing with Phil Mickelson, to a tie for fourth with Tiger Woods. Mickelson and Woods will play together, and Baddeley will play with Angel Cabrera.
'Obviously, being three back, I'm going to have to shoot a good score,' Baddeley said. 'But I'm looking forward to it. I love this course, I love playing here, and I feel like I'm playing great.'
At least he spent some time in the lead. Second-round leaders Rich Beem and Mike Weir fared even worse.
And they needed it much more.
Weir needs to finish tied for fifth or better to advance to the next round of the PGA Tour Playoffs, but he shot a 74 and fell to a 21st-place tie. Beem needs to place no worse than second, but he came in with a 73 in the third round and fell to 14th.
The top 70 players in the standings, and ties, advance to Chicago. The top 30 move on from there to the Tour Championship.
AND HE GOT TO SEE TIGER PLAY, TOO
Phil Mickelson took some time out from the Deutsche Bank Championship to take his kids to a ballgame.
And not just any ballgame.
After shooting a 7-under 64 in the second round on Saturday to move into contention for the lead, Mickelson headed over to Fenway Park to see Red Sox rookie Clay Buchholz no-hit the Baltimore Orioles.
'I was able to take my kids to Fenway Park, and that's an experience in and of itself,' Mickelson said. 'But to have a no-hitter thrown, the atmosphere was electric the last three innings. It was so exciting.'
Buchholz is just the 17th rookie to throw a no-hitter in baseball history, and just the third to pitch one in one of his first two major league starts. Mickelson wasn't taking any credit for bringing the lanky Texan luck.
'I'd like that to rub off on my own game,' Mickelson said.
Mickelson shot 70 in the first round, but went 10 under over the next two days and sat third, two strokes behind leader Brett Wetterich. He will play with Tiger Woods on Monday for the third time in four days.
ONE LAST CHANCE
Steve Flesch made bogey on his final hole Saturday to finish at 1-over 143 and figured he had missed the cut. It was a big blow, for Flesch is No. 70 in the playoff standings, and only the top 70 advance to Chicago next week.
'I had packed up my bags and was looking forward to a four-week break,' he said.
Alas, some late bogeys in the second round moved the cut line, and Flesch got in on the number.
And he still might get that long vacation.
Given new life, Flesch traded two birdies and two bogeys and shot an even-par 71, leaving him in a tie for 65th and unlikely to hold his position in the playoffs.
That was fine by him.
The Deutsche Bank Championship is his 16th tournament in the last 18 weeks -- all he has missed are the U.S. Open and the Wyndham Championship in Greensboro, right before the playoffs began.
Flesch was going nowhere until he won in Reno, which qualified him for the PGA Championship and the FedEx Cup finale. He is tired and not exactly playing his best golf.
'I couldn't even win my club championship right now,' he said.
Steve Stricker was in a panic Sunday, and it had nothing to do with his golf.
He is staying in Providence during the Deutsche Bank Championship, and thought he gave himself plenty of time to get to the TPC Boston. But as he turned off the highway, he found himself stuck in traffic so thick that none of the cars was moving.
'We had an hour and 15 minutes before my tee time,' Stricker said. 'I called transportation because I was concerned about just sitting there.'
Tournament officials suggested an alternate route, and Stricker arrived with plenty of time to warm up. He eagled the last hole for a 69, putting him five shots out of the lead.
The pairing of John Senden and Robert Allenby didn't spend much time hanging around the 18th green.
Both eagled the par-5, 528-yard finishing hole on Sunday in the third round of the Deutsche Bank Championship. Senden left himself just a 4-foot putt, and Allenby sank his from under 12 feet away.
They had two of the nine eagles at the hole, which made it the easiest on the TPC Boston course. The toughest was No. 13, a 451-yard par 4, where the field had just four birdies, 14 bogeys and two double bogeys.