Caspian Gold Cup runner-up Clan Des Obeaux has suffered a setback and could miss the Cheltenham Festival.
Paul Nicholls' charge was last seen when chasing home Guitar Pete in the December showpiece, conceding 21 pounds to the winner.
"Clan Des Obeaux has thrown a splint," said trainer Paul Nicholls. "I've just been struggling with him. He has been intermittently lame for two weeks and we couldn't find out why and Tuesday night he threw a splint. We will try to get him back for Cheltenham, but we will more likely go for Aintree."
Nicholls has been forced to rule out smart novice chaser Give Me A Copper for the rest of the season.
Part-owned by Sir Alex Ferguson, the eight-year-old was last seen winning at Kempton in November.
While the problem is not serious, it is enough to draw stumps, with the Ladbrokes Trophy at Newbury an early big-race target next term.
Nicholls said: "Give Me A Copper is out for the season. He just got a little jarred up after Kempton. We will come back with the view of having a run in a graduation chase en route to the Hennessy (Ladbrokes Trophy). He will be back next season. He is an exciting prospect and he still will be."
