Nicky Henderson has said there is nothing to explain Shishkin's poor run in the Queen Mother Champion Chase at Cheltenham that saw the fancied runner pulled up, bar the heavy going.
The 5/6 favourite never got going and was taken out of the race by Nico De Boinville after the eighth fence after toiling in the rain-sodden ground.
Henderson has ordered tests on his eight-year-old but as yet nothing has come to light to explain the flop which saw rival Enegumene make it 1-1 in the battle between the pair.
"There are little bits and pieces we are still checking out," said Henderson.
"He just never went a yard. There's nothing completely obvious that is wrong but there was clearly something which wasn't right, so we're still checking on everything.
"He looks bright in himself but there's nothing obvious.
"I don't see any reason why he won't make Sandown, anyway."
Seven Barrows trainer Henderson generally enjoyed a decent festival so the Shishkin saga didn't take away too much of the gloss.
"Everything else ran fantastically well, we had six seconds and had another load placed," said Henderson.
"The one that got away was possibly Mister Coffey (Kim Muir). He was my sort of dark horse for the week and I'd been tipping him up at all the previews and it so nearly paid off.
"First Street (County Hurdle) ran a hell of a race, Marie's Rock (Mares' Hurdle) was brilliant, Epatante (Champion Hurdle) ran really well - they ran great across the board.
"We're looking at Aintree for Epatante, we've never tried two and half (miles) with her.
"As for Champ, I'd like to keep him on a flat track. I'm not sure Cheltenham's suiting him at the moment. It's just an idea, we're in discussions. He travelled very well in the Stayers'. We've a few things to sort out with a few of them."
Meanwhile, Shishkin is expected to re-assert what he can do with a Celebration Chase run on the last day of the season at Sandown.
