Ryder Cup captains Paul McGinley and Tom Watson edged closer to revealing their opening pairings with the make-up of Wednesday's practice groups.
Both skippers sent out their sides in three groups of four to help clarify the make-up of their teams for Friday.
The European team began with Rory McIlroy, Martin Kaymer, Victor Dubuisson and Graeme McDowell.
McGinley has already hinted he may split up Northern Irishmen McIlroy and McDowell for tactical reasons.
The pair have managed just two wins in six Ryder Cup matches.
McDowell admitted McIlroy's rising stature as a four-time major winner and world number one has changed the dynamic and could mean the end of their partnership in the fourballs.
The 35-year-old McDowell, the 2010 US Open champion, said he had been getting to know enigmatic Frenchman Dubuisson, which could suggest they will be teaming up this week.
The second European group featured English duo Ian Poulter and Justin Rose, Spain's Sergio Garcia and Swede Henrik Stenson.
"Truly, I feel like with this team I can see so many pairings," said Garcia. "I can see everybody playing with everybody.
"We all get along great. We love each other and we enjoy each other's company. It doesn't matter if it's a rookie or a veteran. I see like a lot of depth on this team, which is very nice."
Close friends Poulter and Rose won both their foursomes matches at Medinah and two of three matches at Valhalla in 2008 and are sure to team up again at Gleneagles.
Ryder Cup stalwarts Thomas Bjorn of Denmark and England's Lee Westwood accompanied debutants Stephen Gallacher of Scotland and Wales' Jamie Donaldson in the final quartet.
"We're pretty much on target with the skeleton plan," said the European captain.
"I'm meeting with the vice-captains today [Wednesday] and we'll solidify that going into the final practice round.
"The interaction from the players has been great. The caddies have given me a lot of information and are very much on side."
Playing from the ninth tee earlier on Wednesday, the first group out for the USA was Zach Johnson, Hunter Mahan, Webb Simpson and Bubba Watson.
Two-time Masters champion Watson and former US Open champion Simpson won two of their three matches by 5&4 at Medinah two years ago, a significant factor in Simpson earning a wildcard from captain Watson this time.
The pair are close friends and are likely to feature prominently for the USA.
The second group comprised Keegan Bradley and Phil Mickelson, alongside Rickie Fowler and 35-year-old rookie Jimmy Walker.
The 44-year-old Mickelson, playing in his 10th Ryder Cup, took excitable rookie Bradley under his wing in Chicago two years ago and the pair thrived, winning all three of their matches together.
The final USA practice group, going off the first tee, consisted of veteran Jim Furyk, Matt Kuchar and rookies Patrick Reed, 24, and Jordan Spieth, 21.
"We are not set in stone," said US captain Tom Watson, who led the USA to victory in 1993. "There's a little bit of give and take here and there and discussion, who is going to play with whom; if one match is really successful, do we keep them together? If they are not successful, do we split them up?
"We kind of have an idea of who is going to play with whom at the beginning, but after that you're coaching and you're captaining by the seat of your pants."
Friday's opening session from 07:35 BST will be four fourball matches, where players hit their own ball and take the best score. The afternoon will be foursomes, in which players use one ball and hit alternate shots.
|Ryder Cup 2014 on the BBC|
|Friday, 26 September: BBC Radio 5 live, 09:00-19:00. The Ryder Cup Highlights: 20:30-22:00, BBC Two; 20:30-22:00 BBC Two Scotland; 23:05-00:35 BBC Two Wales; & 20:30-22:00, BBC Two NI.|
|Saturday, 27 September: BBC Radio 5 live, 09:00-18:30. The Ryder Cup Highlights: 20:30-22:30, BBC Two.|
|Sunday, 28 September: BBC Radio 5 live, 11:00-18:30. The Ryder Cup Highlights: 19:30-21:30, BBC Two.|
|Live text & radio commentary, and video highlights, of all three days available on the BBC Sport website.|