Sir Michael Stoute has voiced concerns about the prospect of fast ground for last year's winner Workforce in the Qatar Prix de l'Arc de Triomphe at Longchamp on Sunday.

The Newmarket trainer does not want firm conditions in Paris for the four-year-old, who landed Europe's premier all-aged middle-distance race last season.

"I've been really happy with his preparation, but disappointed to hear about the weather forecast because he's a big heavy horse and we do like good ground for him," Stoute told At The Races.

"We're a long way from it at the moment and someone's going to have a look at the track and give us an update. I am concerned about the ground. We're very happy with his condition and it looks a particularly strong renewal of the Arc this year.

"It's disappointing we're having this Indian summer in Paris. He's had a nice break after the King George, like he did last year, and I've been very happy with his preparation."

John Gosden's impressive St Leger winner Masked Marvel was among three horses added to the field today at a cost of 100,000 euros. The Clarehaven handler has taken the decision after the ground was deemed too fast for his initial intended runner in the race, King George hero Nathaniel.

Also put in at the final supplementary stage were Andre Fabre's Meandre and the improving German filly Danedream. The additions took the current possibles up to 16, although the final declaration stage, and all-important draw, is on Friday morning.

Another entry given the green light by connections was Snow Fairy. Ed Dunlop's globetrotter gave So You Think a huge fright in the Irish Champion Stakes and really came into her own at this stage of the season last year, winning two huge pots in the Far East. Frankie Dettori has replaced Ryan Moore in the saddle for her last two races and has enjoyed many big-race successes with Dunlop, including one of Ouija Board's Breeders' Cup wins.

With the sun shining all week in Paris, ground conditions are set to be in her favour leading Dunlop to tweet: "Decision made SF runs in the Arc!! Exciting or what and Frankie rides!!"

Aidan O`Brien has taken out Seville, but the Ballydoyle handler is still represented by So You Think, Treasure Beach and St Nicholas Abbey.