Third in the King George VI Chase after having a breathing operation, the eight-year-old ran poorly when pulled up in the Argento Chase at Cheltenham last month.
Pipe said: "He was given an easy time of things after his race while we tried to get to the bottom of his lacklustre effort and he is now being treated for gastric ulcers. He is back on the gallops and looks well in himself so I will need to speak with his owners and decide the plan of action.
"Tomorrow (Tuesday) there is a forfeit stage for the Gold Cup, Ryanair Chase and World Hurdle and I can inform you that he will be scratched from the Gold Cup but will be left in both the Ryanair Chase and World Hurdle."
His two Exeter winners, Vieux Lion Rouge and The Liquidator, are in contention for the Champion Bumper, while Broadway Buffalo remains unbeaten after his hurdling debut at Newcastle.
Pipe said of Broadway Buffalo: "His jumping improved as the race went on and by the time they reached the long Newcastle straight he was pinging his hurdles.
"With the right horses coming to the forefront, the way in which he comfortably drew 17 lengths clear of his rivals bodes well for the future. He is entered in the Neptune Investment Hurdle and the Albert Bartlett at next month's Festival."
Finian's Rainbow, meanwhile, will be Nicky Henderson's representative as the yard bids to replicate last season's success with Riverside Theatre in the Betfair Ascot Chase.
Last year's Queen Mother Champion Chase winner will need to perform better than he did on his only appearance this season, when last of four behind the reopposing Captain Chris in the Amlin 1965 Chase at the same course in November.
Captain Chris subsequently got to within a neck of winning the King George, while Joe Tizzard's classy Cue Card is also in the line-up. Jonjo O'Neill has dual Ryanair winner Albertas Run among the 11 entries for a first run of the season, with Somersby another in the field.