Rory McIlroy might have added Ryder Cup stars Martin Kaymer, Luke Donald and Patrick Reed to a stellar field but the world No 1 is believed to be chasing an even bigger name for next month’s Dubai Duty Free Irish Open — Phil Mickelson.

While Tiger Woods’ agent confirmed during the Masters that the 14-time major winner is unavailable for the May 28-31 test at storied Royal County Down, sources close to the organisation of this year’s extravaganza insisted yesterday that McIlroy has not given up hope of adding left-hander Mickelson to what is already a star-studded field.

“People always talk about the glory days of the Irish Open,” Championship Director Antonia Beggs said at the Newcastle venue yesterday. “But I don’t think the glory days of the Irish Open are in the past any more. I think they are very much in the present.”

She then added: “This isn’t the last announcement we are making before the Championship. We were at the Masters last week and were slightly overwhelmed that Irish Open was a real buzzword around Augusta amongst the players and the various tours. 

“That really opens the doors when you are talking to management companies. With the BMW PGA at Wentworth the week before the Irish Open, that shows there is a synergy between the two events. 

“So there may be more player announcements to come. Rory hasn’t finished asking people yet! And we want to be strategic about this. This isn’t a one off. We want this event to grow and grow and grow. And we want to save some players for the future, potentially, about what we can do.”

The addition of US Open champion Kaymer and Ryder Cup stars Reed and Donald to a field that already features Ireland’s major winners Darren Clarke, Pádraig Harrington and Graeme McDowell as well as the the likes of US star Rickie Fowler, four-time major winner Ernie Els, Sergio Garcia and Lee Westwood has helped secure a 25% increase in the prize fund to €2.5 million.

That makes this year’s tournament the biggest since the prize fund was slashed from €3m to €1.5m following the exodus of sponsors 3 Mobile after the 2010 edition in Killarney

But while tournament host McIlroy — he's staging the event to boost not just his home Open but also his Rory Foundation — has written notional IOU’s to his friends, promising to repay their loyalty by making return appearances in their charity events or other favours, the European Tour is convinced that Royal County Down itself has also played a huge part in attracting such a strong field for what will be a 20,000-a-day sellout.

Just three of the world’s Top 50 teed it up at Fota Island last year — McIlroy, McDowell and Scotland’s Stephen Gallacher. But there will be no fewer than five of the world’s current Top 20 at Royal County Down next month with McIlroy, Fowler, Reed, Garcia and Kaymer all confirmed starters.

“There is no doubt that the links product is very attractive for Tourism Ireland, which is charged with promoting the island of Ireland abroad” said James Finnigan, Commercial Director of the Irish Open. 

“Yes, the players who have decided to come this year have had encouragement from Rory. But we shouldn’t underestimate the key part that Royal County Down — the world’s greatest links golf course — has played in attracting them.

“A lot of the players in the field haven’t been seen in Ireland since the Amex in 2004 or the 2006 Ryder Cup. Just three of the 2006 European Ryder Cup team played in the 2007 Irish Open at Adare Manor. But we can say safely that we will have more than three at Royal County Down in the last week in May.”

The Golf Channel will have a crew at the Irish Open for the first time thanks to the presence of Mcllroy, Fowler and Reed. But should McIlroy succeed in persuading Mickelson, the left-hander will have played all the great Irish links following his Walker Cup appearance at Portmarnock in 1991 and his previous visits to the likes of Lahinch, Ballybunion and Royal Portrush.

European Ryder Cup skipper Clarke conducted a teleconference at Royal County Down and believes the addition of Donald, Reed and Kaymer to the field is a compliment to McIlroy and sign that American players know it’s important to travel to improve.

“The fact he has got so many of the world’s top players coming to play is testament to how much they think of Rory and the esteem he is held in already,” said Clarke, who will be bidding for an elusive Irish Open win for the 24th time. 

“If you take a look at what Tiger did to become the best player in the world, he played all over the world  in different places. Patrick Reed is still at the early stages of his successful career but he is obviously taking that on board and he is looking to play more outside of America, which can only be good for an event such as the Irish Open and the PGA.”

As for his own Irish Open quest, Clarke said: "I’ve won at the K Club in the European Open, but it wasn’t the Irish Open, so it’s one that I have always wanted to win. 

"If you ask any professional, they would want to win their home Open, so it’s one I have always tried to play well in. I haven’t managed to do it that often. Invariably I’m  in one of the first groups starting off on a Saturday morning. 

"I don’t want to be doing that year after year, but hopefully being back on links on a course as good as Royal County Down I’ll have a little more success.”

The Irish Open will be played in Northern Ireland again in 2017, when it goes to Lough Erne. But while there is no venue yet for 2016, the European Tour is pleased that Fáilte Ireland has come on board again as an associate sponsor for an undisclosed amount.

“That’s good news,” Finnigan said of the Fáilte Ireland investment. “Their commitment for 2016 has yet to be confirmed and is still a work in progress. But looking at the product we are developing, we think it would be foolhardy for the government to try to walk away from this product at this stage given the way it is developing. 

"And we look forward to working with An Taoiseach Enda Kenny and his officials and hope the see what their counterparts in the Northern Ireland Executive are doing. We are hopeful of retaining the level of investment at the right level.”

As for the question of the distribution of the eight sponsor’s invitations, it remains to be seen what balance the Tour and McIlroy will strike between the stars and struggling Irish players such as Peter Lawrie, Gareth Maybin, Simon Thornton or Kevin Phelan, all of whom lost their cards last season.

As for Clarke, the Dungannon man is now a resident in Portrush and while he can't remember the last time he played Royal County Down, he knows it's different to most links tests.

"When I have Royal Portrush on my doorstep, I don’t need to travel too far to play good links golf," Clarke said, nearly sidestepping what woudl otherwise seem a strange omission. "I can’t remember the last time I played Royal County Down, it’s not recent anyway."

Whatever his feeling about the blind shots on the course, he said: "The immediate difference it has to any of the world’s top class links courses is that you must hit the ball up over hills. Added to that, the conditions, if it’s windy, are going to make a little bit of local knowledge all the more important, particularly with lines off the tees.

"Invariably you’re hitting to posts in the distance so you have to make sure you do all your preparations properly. If there’s a breeze the course is going  to play very tough but I hope it’s going to be a massive success.

"I can imagine there will be huge crowds, especially with the top class field we’ll have. They’re going to be in for a treat with the quality of players that will be there and Royal County Down itself for people who haven’t been there before."

The quality of field, as Clarke pointed, is a testament to the pulling power of McIlroy as world No 1 and his commitment, not just to his charitable foundation, but to Irish golf.

"Rory is very proud of his Foundation," Clarke said. "Obviously he started at a very young age. He is very very proud of all the work that he does and he pulls in a lot of favours to get guys come over and play.

"The fact he has got so many of the world’s top players coming to play is testament to how much they think of Rory — the esteem he is held in already. It is the strongest field for the Irish Open for a very long time. It is a huge positive for the European Tour because it gets so many world ranking players on one of the best golf courses in the world.

"Rory’s team in the first year the Rory Foundation is involved so much is a huge statement as to what he wants to achieve and to help the Irish Open move on."