Rostropovich looks set to represent leading trainer Aidan O`Brien in the Rothmans Royals St Leger at Doncaster on Saturday.
O`Brien also has Lermontov entered in the 14-furlong Classic as well as the the ESAT Digifone Champion Stakes and Listed Palmers Golden Ball Foxrock Stakes at Leopardstown on the same afternoon.
However, following the news that Montjeu is to miss the Irish Champion Stakes the Ballydoyle trainer could now aim Giant`s Causeway at the 10-furlong Group One contest.
He said: 'If Giant`s Causeway runs in the Champion, at this stage, Lermontov could run in the Listed race at Leopardstown and that would mean Rostropovich would probably run in the St Leger and Joplin would run in the Flying Childers.'
George Duffield is on stand-by to partner O`Brien`s Leger hope.
Rostropovich, who finished last of five behind Royal Rebel in the Group Three Lonsdale Stakes at York on his latest start, is a best-priced 50-1 with William Hill for Doncaster.
Connections of outsider Going Global are hoping the colt can show his best form in the St Leger when he will be visored for the first time.
'I`ve been waiting to put a visor on him _ he`ll wear one at Doncaster,' trainer Sean Woods said today.
'But the ground is the key with him. Any rain at Doncaster will improve his chances no end.'
Going Global, a 66-1 chance with William Hill, got off the mark for the season at Ripon in April before finishing third to Sakhee in the Classic Trial at Sandown and a neck second to Saddler`s Quest in the Lingfield Derby Trial.
Those runs all came with plenty of give underfoot and the son of Bob Back has disappointed on his four starts on firmer going since, including last time when fourth of five behind Alva Glen in the March Stakes at Goodwood.
'It`s my fault for running him on fast ground,' said the Newmarket trainer.
'Obviously he`s a long shot in the Leger but his early season form stands up well.
'He`s fit and well and ready to run and Richard Hughes will ride.
'Tactics aren`t a problem with Going Global. He`s very genuine and anything suits.'
Coral report money in the St Leger today for Marienbard and have cut his odds to 6-1 from 7-1. Air Marshall remains 9-4 favourite.
Rothmans Royals St Leger betting:
Coral bet: 9-4 Air Marshall, 4-1 Millenary, 5-1 Savoire Vivre, 9-2 Dalampour, 6-1 Marienbard, 7-1 Littlepacepaddocks, 16-1 Lermontov, 20-1 bar.
William Hill: 5-2 Air Marshall, 7-2 Dalampour, 4-1 Millenary, 9-2 Savoire Vivre, 13-2 Littlepacepaddocks, 7-1 Marienbard, 20-1 Kuwait Trooper (from 33), 25-1 Lermontov, 28-1 Talaash, 40-1 Chimes At Midnight, 50-1 Rostropovich, 66-1 Going Global.
Ladbrokes: 5-2 Air Marshall, 7-2 Millenary, 9-2 Dalampour, 5-1 Savoire Vivre, Marienbard, 7-1 Littlepacepaddocks, 20-1 Lermontov, 25-1 Kuwait Trooper, 33-1 Rostropovich, Chimes At Midnight, Talaash, 40-1 Media Puzzle, 50-1 Going Global.
