ST LOUIS - Defending champion Justin Thomas enters the 100th PGA Championship having clinched a berth on the US Ryder Cup team, with four more spots up for grabs this week at Bellerive.

Thomas secured his place Sunday by winning the WGC Bridgestone Invitational, joining world number one Dustin Johnson, reigning Masters champion Patrick Reed and two-time US Open winner Brooks Koepka. "It's always an honor to represent your country," Thomas said.

He downplayed any knowledge gained from playing in the French Open in June at Le Golf National, where the Ryder Cup will see holders United States try to win in Europe for the first time since 1993. "It's not like there's any groundbreaking stuff I learned," Thomas said. It's not anything crazy or anything tricky. You have to drive it straight. It's all right in front of you."

Four other Americans will become automatic qualifiers for the biennial team showdown against Europe next month based on point totals following Sunday's final round of the year's last major tournament. Three-time major winner Jordan Spieth, who would complete a career Grand Slam with victory this week, and Bubba Watson, a two-time Masters champion, likely have enough points to hold off rivals and make the September 28-30 matches.

In more precarious positions are Rickie Fowler and Webb Simpson, who leads Bryson De Chambeau by just under 49 points for the final spot with Phil Mickelson, an 11-time Ryder Cup player, just under 158 points back.

Xander Schauffele, Matt Kuchar and Tony Finau are next on the points list and US captain Jim Furyk is conveniently paired with Finau and Schauffele for the first and second round this week as he ponders four captain's picks to be made in early September.

"I really need to see what we have with our top eight, who exactly those are going to be," Furyk said. "Six of those guys are probably mathematically locked and probably can't fall out of the points. But we'll see where we stand.

"Then the guys we're adding in, we want the best players. We want the guys that are in pretty good form right now. I'm very comfortable with my team. I'm not sure we'll be lacking that much."

Simpson could be in trouble should he slip from the top eight, having gone 2-3 with one halved in Ryder Cup play, and was benched in 2014 at Gleneagles. Players who can attack with their second shots will be crucial for success at Le Golf National, says Furyk.

"It's going to be about getting the ball in the fairway, but then you're going to have some short irons," Furyk said. "You're going to have a lot of wedges and I think the guys that can attack from those distances and knock some putts in. That's going to be a key."