THE laws of probability said it had to happen - after a brilliant start to the season, former champion trainer Henry Cecil has hit his first hurdle. And it is a big one. A concerned Cecil remained 'hopeful' last night that the unbeaten Bosra Sham can make it to post for the Pertemps 1,000 Guineas at Newmarket on May 5 despite a recent injury setback. The filly sustained a bruised near-fore foot, which is expected to keep her on the easy list for a crucial period only days before the Classic. She had been virtually unbackable at 2-5 following her recent Newbury win. But rather than panic, bookmakers made few if any alterations to the ante-post market, with Mike Dillon, the Ladbrokes representative, reminding punters: 'A similar thing occurred to Nashwan before his Derby win in 1989.' It is ironic that Bosra Sham has suffered a setback so close to the big-race target that she has threatened to totally dominate. After making a winning seasonal debut in the Fred Darling Stakes, Cecil made the point that everything had gone according to plan in preparation for the 1,000 Guineas. 'I have been able to do everything I wanted to do with her leading up to her first race,' the former champion trainer reported. Now, at the worst possible moment, the filly has suffered a reverse. 'It is a slight setback, but hopefully she will be back in exercise in a couple of days,' said Cecil. 'Hopefully the setback will not affect her participation a week on Sunday.' Cecil has enjoyed a wonderful start to the new Flat season, with Storm Trooper emerging as his 2,000 Guineas colt and a string of Derby types, headed by Silver Dome in this weekend's Thresher Classic Trial at Sandown Park, waiting to be fully tested. But now all the trainer's attention will focus on getting Bosra Sham back to peak fitness for the 1,000 Guineas. 'Frankly, I'm hopeful that we'll get her there,' the trainer said. 'But it is not going to be easy. It is not an ideal situation to have so close to the race.' Bookmakers Hills have left Bosra Sham unchanged at 2-5 at the top of their 1,000 Guineas market, with Bint Salsabil at 9-2 and Bint Shadayid at 7-1. The latter two fillies, both owned by Sheik Hamdan Al-Maktoum, could well be split, with one tackling the Newmarket Guineas and the other being diverted to Longchamp for the French equivalent on May 12. John Reid has accepted to the ride on the Michael Stoute-trained Dance Sequence, winner of the Lowther Stakes at York last year. Sea Spray, trained by Peter Chapple-Hyam and one of Reid's regular mounts, is more likely to by-pass Newmarket in favour of the Irish 1,000 Guineas at the Curragh on May 25.