Snedeker closed with a 5-under-par 65, leaving him at 21-under 259.
On the day that Brandt Snedeker played a more normal round of golf, he held the top spot in the Wyndham Championship by the end of Friday's play.
The Wyndham Championship takes place at Sedgefield Country Club in Greensboro, North Carolina.
Injury-cursed Paul Waring won his first European Tour title at the 200th attempt on Sunday with a play-off triumph over South Africa's Thomas Aiken at the Nordea Masters. The 26-year-old former University of Washington golfer had a bogey-free round until the tournament's 72nd hole. He was playing in the group in front of Snedeker.
Simpson, the 2011 champion, shot 62 in the last round.
"When you don't have your health out here and you're trying to fight through it, it's really tough because you know what you're capable of and your body's not letting you do what you think you should be able to do.", Snedeker said after the round. The eighth-place tie was his best result of the season. Cheng Tsung Pan was tied for the lead with Snedeker going into the his 18th hole of the championship. The leaders will start at 1:15 p.m. It's only my second year on the Tour. Patrick Reed accomplished the feat in 2013.
Points bagged an eagle on the par-3 second hole with a 152-yard shot from the fairway but was only 2 under the rest of the way.
Points, a three-time PGA Tour victor, who missed 15 of 16 cuts before tying for 40th at the Barbasol Championship in July, said he'd benefitted from a new set of irons - and from playing without any expectation of making it to the FedEx Cup playoffs coming up.
Thirty players were still on the course when play was halted during the mid-afternoon with thunder booming and a threat of lightning.
The top 125 on the season-long points list advance to the four-event FedExCup playoffs that start next week.
Yang shot 65. Defending champ Lexi Thompson was five shots back after playing 27 holes in 10 under Saturday, posting rounds of 68 and 64.
He finished well outside the eight automatic qualifiers for the American team after last week's cut-off.
Spaniard Sergio Garcia (70) ended the tournament tied for 24th at 12 under, a shot adrift of Henrik Stenson (64).
Snedeker said he has played as many as 36 holes in a day on the PGA Tour when weather-related issues have scrambled schedules. A day earlier, storms forced a suspension of play, so 30 golfers completed their third rounds Sunday morning. They said they expect the final round to begin in the late morning, grouping the players in threesomes starting from both the first and 10th tees.