Lawrie, who last represented Europe way back in 1999, leads the Johnnie Walker Championship at Gleneagles by one from Frenchman Romain Wattel after a third-round 67.
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Belgian Colsaerts, meanwhile, needs a top-two finish to knock Martin Kaymer out of the last automatic spot on Jose Maria Olazabal's side, but a one-under-par 71 has left him in joint 13th place.
It may not matter what he shoots in the final round, however.
Unless Padraig Harrington wins in America the big-hitting Colsaerts is the name on just about everyone's lips as the expected choice to join Ian Poulter as a wild-card.
Thomas Bjorn, one of the four assistant captains along with Darren Clarke, Paul McGinley and now Miguel Angel Jimenez as well, had dinner with Olazabal on Friday night.
"I think he's pretty much where he wants to be with the team," he said.
"He's pretty certain what he wants to do and there's only a few people that can really rock the boat if they win the last tournament.
"We talked about a lot of things - including obviously Nicolas Colsaerts, but a lot of other players.
"I think he listened to all of us and he's got to make a decision Monday morning.
"We can only give him information and say what we see out there. He's pretty cool and he's studied everybody down to the last detail.
"He knows what he wants to do and what team he wants to bring - and that's a good thing I think.
"He's very much in good spirit about what he's got."
Colsaerts is prepared to be kept on tenterhooks for another day at least, however.
"I have no clue - you can look at so many different scenarios," he said. "What I need to do is shoot the lowest round of my career.
"I'm thinking about it all the time. When you want something that much it's difficult to avoid."
He is aware of a wild-card threat not only from Harrington across the Atlantic - despite Olazabal saying the Dubliner needs "at least a win" - but also in Scotland from Spaniard Rafa Cabrera Bello, who could yet finish ahead of him on the points table.
Lawrie, though, has his focus solely on trying to win on home spoil for the third time.
The first of those was the 1999 Open Championship - the victory that led to his Ryder Cup debut - and then he added the Dunhill Links title at St Andrews in 2001.
Lawrie ended nine years without a victory in Spain last year and has looked good for a second cap ever since he triumphed in Qatar in February and then finished runner-up to Luke Donald in the BMW PGA Championship at Wentworth in May.
He resumed one behind joint halfway leaders Mark Foster and Richard Finch, but the two Englishmen had shockers - 75 and 78 respectively.
In stark contrast to that, 21-year-old Wattel shot a 63 that would have equalled the course record but for preferred lies being in operation on the wet fairways.
Lawrie calmly went about his work, though. Three birdies took him to the turn in 33 and while he did bogey the 10th and 15th there were also four more birdies on the inward half.
The last of them came despite his ball plugging in the sand by the green at the long 16th. He holed an eight-footer there, then got up and down from another bunker at the next.
Asked if experience had served him well the 43-year-old from Aberdeen smiled and answered: "I'm just old!"
Not as old as his 1999 cup partner Colin Montgomerie, but the 49-year-old believes again he might yet become the Tour's oldest-ever winner - if not now, then very soon.
After a 69 for seven under Montgomerie said: "That's the best golf I've played in a number of years. I'm very disappointed not to shoot a lot lower.
"My belief was non-existent. This has re-ignited some fire, which is great."
And on the Ryder Cup situation Europe's 2010 captain commented: "You've got to think of Poulter and Colsaerts really. It will be no surprise if that's what he (Olazabal) decides."
There was one proviso in that - if Harrington wins in New York on Sunday. But it has become a big "if".