Rory McIlroy has urged the European Tour to scrap its rule barring non-members from competing in the Ryder Cup.
According to McIlroy, the absence of US-based Englishman Paul Casey did not help Europe's cause in Minnesota last month when the hosts won back the trophy by a crushing 17-11 margin at Hazeltine National.
And the 27-year-old four-time major winner is seeking a change in the ruling ahead of the 2018 match in France.
In an article in the Daily Telegraph, McIlory said: "It should be the best 12 players from Europe versus the best 12 players from the US.
"To have a guy like Paul Casey not on our team, when he is playing some of the best golf in the world right now, it definitely hurt us."
Casey, the world No 12, has recorded four top-four finishes in his last six starts on the PGA Tour, but was ineligible for the European team.
The 39-year-old is based in Scottsdale, Arizona, and late last year opted not to retain his membership of the European Tour.
Rules state a golfer needs to commit to a minimum of five tournaments in a single season - outside of the four majors and four World Golf Championship events - to be available to qualify for a Ryder Cup spot.
And Lee Westwood has also backed McIlroy's call for a change in the rules: "I can see the reason why they want you to be a European Tour member, but I think it's unfortunate when you have clearly world class/Ryder Cup experienced players missing out because they have chosen to, for one reason or another, live in America or play golf solely in America.
"I can always sympathise with them because I don't see why that personal decision should affect whether you can play in the Ryder Cup or not.
"At the end of the day, you're still European and you still have the passion to play for Europe and represent them.
"If you prove that you're world class on, say, the PGA Tour and not the European Tour, why should that have any bearing on whether you can play or not."