The Open door has closed a little bit tighter it seems.

For those golfers pitching up in the last chance saloon of the Scottish Open in July with lingering hopes of earning a place in the following week's Open Championship, the mission is simple; it will be a case of win or bust.

Peter Dawson, the chief executive of the Royal & Ancient, last night unveiled changes to the exemption criteria for the game's oldest major and one of the key alterations affects the domestic showpiece.

In previous years, the leading player in the top five of the Scottish Open, who was not already exempt into the Open, would qualify. Scott Jamieson earned a place in the 2011 Open at Sandwich by taking third at Castle Stuart the week before but, as of this year, only the winner will earn a coveted tee-time.

Speaking yesterday at Muirfield, the host venue of this July's Open, Dawson admitted that the sheer number of exemptions, and the various avenues from which players can gain a place in the field, had caused a moment of panic ahead of last year's championship at Lytham and had prompted the rethink.

"We were given something of a fright because the way the exemptions fell. At one point, we had 161 competitors," he said. "Playing with a bigger field would have been difficult but, fortunately, we got away with it and because of scratchings and injuries we eventually got back down to our usual field of 156 but that caused us to look at our exemptions and cut them back."

Will the decision have a negative impact on the Scottish Open, which takes place from July 11-14 at Castle Stuart? "I think players who go to the Scottish Open are concentrating on that, not the Open Championship. It [Open qualification] is a nice side benefit for sure but the Scottish Open is a very strong event in its own right."

The French Open, which offered a similar qualification route to the Scottish Open, has had that benefit withdrawn while, in America, only the winner of the John Deere Classic will qualify. Another tweak to the system will lead to the European leg of International Final Qualifying at Sunningdale having its number of Open spots reduced from 10 to nine.

Any vacant places will be filled from the world rankings and Dawson is confident the changes will not affect the strength of field at the Scottish Open.

The following week the 142nd Open will take place at Muirfield, with the course's popularity among players set to be tested by an extra 158 yards and "plenty of rough". New tees have been added on seven of the holes, taking the overall distance from 7034 yards, when Ernie Els won in 2002, to 7192 yards (par 71) this summer.

The biggest difference is on the ninth, where a land swop with neighbours the Renaissance Club has made it possible for the tee to be moved back almost 50 yards, extending the par-5 hole to 554 yards, with a new bunker added on the right of the fairway and other bunkers moved closer to the green.

"We are absolutely delighted to be back at Muirfield for the 16th time," Dawson said. "It's immensely popular with the players . . . but we will be setting the course up to challenge these golfers. The rough has been cut down over the winter but will regenerate over the coming weeks. The amount of rough is weather-dependent, but we will get plenty."

During a general discussion, the prickly issue of pace of play again reared its head. In the wake of the one-stroke penalty for slow play that was meted out to Chinese 14-year-old Guan Tianlang at the Masters, critics roared that officials had picked on an easy target. "We treat everyone the same," insisted Jim McArthur, the chairman of the Open's championship committee. "In terms of dealing with amateurs against professionals, there is no discrimination in how they're dealt with. We are determined to do whatever we can on slow play, and that applies to the Open Championship. There is a schedule that we will be applying stringently in the Open."

In the wider scheme of affairs, Greg Norman's rant that golf's anti-doping procedures are "disgraceful" and that blood testing needs to be introduced as soon as possible, prompted a rapid response from Dawson. The on-going saga surrounding Vijay Singh and his use of a banned substance continues to cast a shadow over the game.

Dawson said: "We have a medical team working at the IGF [International Golf Federation] now looking at golf's testing regime and coming up with recommendations for what's going to happen pre-Olympic Games. So the issue of blood testing is up for consideration at the moment."