Grinkov has been made a 13 to 2 favourite to fill a rare big-race blank for Charlie Swan in Sunday's Pierse Handicap Hurdle, but who will carry the all-important top weight in the Leopardstown feature is not certain.

A total of 29 horses are left in the £100,000 contest, formerly known as the Ladbroke and the Sweeps Hurdle, but significant defections are likely to continue.

Balla Sola, the original top weight, defected yesterday but while the next highest-rated horse, Topacio, remains in the race at the moment, his trainer Pat Hughes describes him as "unlikely" to run.

Hughes has five entries remaining, including the ante-post favourite, but only four are set to take part and the trainer said yesterday: "Topacio looks like being the odd one out. No one wants to carry top weight and neither do I. Topacio is not a lover of very soft ground and 11-10 is a lot for a five-year-old."

The Jonjo O'Neill-trained Master Tern was also taken out yesterday and the only possible cross-channel raider is the Philip Hobbs-trained Rooster Booster.

That hasn't stopped one punter swooping in with a £2,000 bet struck at 8 to 1 on Grinkov with Paddy Power and that firm now make the Hughes runner their 13 to 2 market leader. Grinkov is a 6 to 1 favourite with Cashmans.

Sunday's big race is one of the few significant blanks on Charlie Swan's big race CV and he teams up with Hughes who won the race with Mantles Prince last year.

The big-race specialist, however, is Arthur Moore who reported yesterday he will run three in the Pierse Hurdle including The Gatherer who is a 9 to 1 joint-second favourite with the other J P McManus-owned runner, Spokesman.

Moore has won the race six times in its various guises, including four times in the 1980s, and said yesterday: "I've three left in, The Gatherer, Masalarian and Ellenjay, and all three will run, but I've no idea about jockeys yet. The weights going up won't help."

The ground at Leopardstown is currently "soft" but the racing manager, Tom Burke, isn't ruling out further improvement on a track that endured such punishment only 10 days ago.

"The forecast is for mainly dry weather and the met' people don't seem to reckon there will be disasterously cold temperatures so the outlook looks good. With almost a week to go, the ground could improve even more," said Burke.