A hoof injury threatens to rule Buffering out of a TJ Smith clash with champion mare Black Caviar.

Trainer Robert Heathcote noticed the problem when Buffering was being led out of his stall to prepare for trackwork on Thursday morning.

"He put in a short stride as he was being led out of his box this morning and we tested his hoof which was showing clear signs of sensitivity," Heathcote said.

"Whether it's a stone bruise or a corn is something yet to be determined but it's not the sort of thing I wanted to be dealing with leading up to a Group One race."

Heathcote is hoping Buffering's hoof problem can heal quickly to enable him to run in the Group One TJ Smith Stakes (1200m) at Randwick on Saturday week.

"This issue could resolve itself in the next 24 hours and I'm hoping that will be the case," he said.

"You can't go into any race less than 100 per cent let alone a Group One against Black Caviar.

"If he's going to run in the TJ Smith it will need to clear up over the weekend."

If Buffering's injury doesn't improve in the next few days and he is ruled out of the TJ Smith, Heathcote will aim him at the Group Two Victory Stakes (1200m) at Eagle Farm on April 27.

On a more positive note for Heathcote, he is pleased with the progress of Toorak Handicap winner Solzhenitsyn leading into Saturday's Group One George Ryder Stakes (1500m) at Rosehill.

Heathcote said Solzhenitsyn faces an uphill battle in toppling champion three-year-old Pierro but believes the gelding is on target for his main Sydney target, the Group One Doncaster Mile at Randwick on April 20.