Three-time major champion Brooks Koepka and world number one Dustin Johnson will play for the US against Europe in September's Ryder Cup in France.
Eight players have already qualified for the 12-man team with captain Jim Furyk set to name four wildcard picks in early September.
Justin Thomas, Patrick Reed, Bubba Watson, Jordan Spieth, Rickie Fowler and Webb Simpson make up the other six.
European golfers have three more events to play before their team is announced.
The final one of those events is the Made in Denmark Tournament, which takes place from 30 August - 2 September.
Europe captain Thomas Bjorn will also make four wildcard picks to add to his eight automatic qualifiers on 5 September, with the Ryder Cup taking place from 28-30 September at Le Golf National, near Paris.
Italian Francesco Molinari, who won The Open in July, currently leads the European standings.
Furyk, who will name three of his wildcard picks on 4 September and make a fourth selection on 10 September, said he and the eight players confirmed for the US team are "excited" as they prepare to defend the title they won at Hazeltine in 2016.
He added: "We talked a lot about the type of player we were looking for on this team and the atmosphere in Europe - the boisterous crowds - and we talked about the team they will have, which will be strong," he added.
"I wanted a team that would really enjoy that atmosphere. Looking at these eight guys they will enjoy this challenge."
Tiger Woods staked his claim for one of the wildcard picks by finishing second to Koepka at the US PGA Championship on Sunday.
The 14-time major champion, who has not won one of the sport's biggest prizes since claiming the US Open title in 2008, also went close at The Open in July, finishing joint sixth.
Asked whether Woods, who is a vice captain, could help the US team as a player in Europe next month, Furyk replied: "That's a good question. He is playing very well. There are probably lot of folks out there who think he can help us.
"Really what we wanted to talk about today is the top eight players. I realise Tiger is a story, that he is playing well, and I'm excited to see that."
Furyk added that he would select another vice captain should he pick Woods as a player.
"Tiger's priceless, to be honest with you," he said.
"He's been really a big help to our captains in both 2016 and 2017 (at the Presidents Cup) from a strategy perspective, from personnel, personalities, and also really serving on the golf course. I mean, walking with players.
"I think it's been a big boost having the best player maybe to ever live following your group and being there for support."