A minor bug in the yard prevented Martyn Meade from running Advertise in Saturday's Sprint Cup, but William Hill St Leger hope Technician is on course for the final domestic Classic of the season after avoiding any ailment.
Advertise, owned by Phoenix Thoroughbreds, was as short as 11-4 for the Group 1 but scoped badly on Friday leading to his withdrawal from the race.
The same bug that derailed Advertise's Haydock bid also put paid to the chances of stablemates Business and Fox Vardy – both of whom had been due to run at Ascot.
Meade said: "We just had a little bit with a few of them, they were just slightly under par. It was nothing serious but it was just one of those things that travels through the air pretty quickly and I thought we should give them the day off.
"It didn't affect every horse but it just happened to be the ones who were down to run this weekend."
One horse unaffected was St Leger hope Technician, who is a 14-1 shot with the sponsors for Saturday's Doncaster Classic after gaining a second Pattern success in the Group 3 Geoffrey Freer Stakes at Newbury last month.
"All systems go," Meade added. "He's in flying form at the moment and he seems very enthusiastic. There's no need to worry about him."
The John Gosden-trained Logician heads the St Leger market at 5-4, with Sir Dragonet next best at between 3-1 and 4-1.
Meade acknowledged his disappointment at missing the opportunity for a third top-level success of the season with Advertise, following victories in the Commonwealth Cup and the Prix Maurice de Gheest.
However, a trip back to Ascot for the Champions Sprint next month is on the cards for the son of Showcasing – for which he is the general 4-1 favourite.
"Advertise is absolutely fine," the trainer said. "It was just a little upper airway irritation and we could have run him but he wasn't absolutely 100 per cent and I thought it would be better not to if we weren't giving him the best chance to win it.
"It is annoying that it happened the day before the race, everything had gone well up until that point. In a few days he should be perfect and the next target has to be the Champions Sprint at Ascot."