Simpson, in a chase to try to win the PGA Tour money title, made a pair of late birdies for a 3-under 67 at the McGladrey Classic. That left him two shots behind Billy Horschel, who picked up four shots over his last four holes on the Seaside course for a 64.
After finishing his second round, Simpson said he would play the PGA Tour's final tournament next week at Disney in his bid to capture the money title. Donald, currently atop the money list by $68,971 over Simpson, had said earlier Friday that he would add Disney to his schedule.
Donald, who was in England for his caddie's wedding, said on Twitter: "There was never really a decision to be made. I have a chance of making history. See you all at Disney next week." That was followed by a hash tag that said, "Bring it on."
Simpson continued to do just that.
After opening with a 63 and facing stronger wind off the coastal waters, he survived a shaky start and poured in enough birdies to get into the lead with Michael Thompson, who had a 64 earlier in the day. They stayed there until Horschel made his late burst with an eagle-birdie-par-birdie finish to take the lead at 12-under 130.
"I figured Luke was going to play," Simpson said. "I think he's kind of thinking the same thing I'm thinking, that if one of us was going to play, the other one really needed to. It's going to be fun. He's one of the most competitive guys on tour, and so I'm sure he's going to come guns loaded, and he's going to play great like he has all year."
Simpson is not entirely focused on next week. He was only two shots behind going into the weekend, poised to make a run at a tour-leading third win this year. That might be enough to make him the favorite for PGA Tour player of the year, and the money list could help sway the players' vote. Donald has a large lead in the Vardon Trophy for lowest scoring average.
Louis Oosthuizen also had little trouble handling the stiff breeze, having grown up in the wind along the South African shore and winning the British Open by seven shots at St. Andrews last year. Oosthuizen, playing his last event on the U.S. tour, had a 67 and was in the group four shots back.
Bud Cauley, the 21-year-old who left Alabama this summer after his junior season, took another step toward becoming only the sixth player to get his PGA Tour card without going to Q-school. Cauley was among the top 10 until running into trouble on the 14th, one of the more exposed holes on the Seaside course, and making double bogey. He still had a 68 and was tied for 17th going into the weekend. In eight tournaments since turning pro, Cauley has missed only one cut.
Horschel, meanwhile, is No. 139 on the money list and says he's not worried — not as he tries to finish among the top 125 to keep his card, or tries to stay in the top 150 to avoid two stages of Q-school.
"I'm not worried about No. 139," Horschel said. "I'm worried about playing well."
Horschel played with Cauley and William McGirt, the long shot of the FedEx Cup playoffs who now is trying to get his card. McGirt took a triple bogey early in his round to fall three shots over the cut line, and then rallied with five birdies to make it to the weekend and keep his hopes alive.
The McGladrey Classic did lose its tournament host, however, when Davis Love III took bogey on the last hole and wound up missing the cut by one shot. Seventy-two players made the cut at 1-under 139. Among those knocked out was Matt Jones, who is No. 125 on the money list. He opened with a 65, but followed with a 75 to miss by one shot.
Simpson also is interested in money, but on the high end of the food chain.
This race was set up a month ago at the Tour Championship, when Donald made a birdie on the final hole at East Lake that put him in a three-way tie for third and earned him enough money to move past Simpson to the top of the money list.
Donald has a commanding lead on the European Tour money list as he tries to become the first player in history to win money titles on the European and PGA Tour.
"His birdie on 18 at the Tour Championship turned out to be the biggest putt of the year for him, in my opinion," Simpson said. "It just kind of turned around our schedules a little bit."
Because the tour tweaks groupings, Simpson expects to be paired with Donald for the first two rounds at Disney.
"A lot is going to happen next week," Simpson said. "And a lot can happen this weekend. I'm just going to try and win the golf tournament. If I can play well this weekend — even if I don't win — a great chunk will be added to the money list."