Trainer Paul Nicholls admits it is a "50-50" chance whether Greaneteen runs in the Queen Mother Champion Chase after an ulcer was discovered in his eye.

Nicholls is seeking to win the two-miler for what would be a record seventh time after last tasting victory in 2020 with Politologue. 

Greaneteen finished fourth in the contest last year, a mere two lengths adrift of eventual winner Put The Kettle On. 

He then responded by going to Sandown and winning the Grade One Celebration Chase and his form has been mixed since returning to racing in November following his summer break. 

After a disappointing fourth at Exeter in the Haldon Gold Cup, he came home to win the Tingle Creek at Sandown. 

He then came second to the imperious Shishkin in the Desert Orchid Chase over the Christmas period. 

However, his last outing in the Dublin Chase at Leopardstown was a huge disappointment, coming last in a five-deep field. 

Another crack at the Queen Mother was planned but now Nicholls concedes Cheltenham Festival may come too soon for the eight-year-old charge due to the problem that has flared up in his eye. 

Delaying his return to Sandown on the last day of the season may now be the target according to the trainer. 

He said: "He's not here at the moment, he's injured his eye. Whether he got hit with a lump of mud or something at Down Royal or got cast in his box, he's got an ulcer on his eye which he is being treated for. 

"It's going the right way, but I think we're unlikely to be able to go Cheltenham with him. 

"Unless I get him back in the next few days, he'll have to wait until Sandown on the last day of the season. He would be 50-50 to be able to run in the Champion Chase."

Greaneteen's absence may mean that Politologue will fly the flag for Nicholls as he attempts to win the race for a second time. 

The 11-year-old romped home to win the 2020 edition, finishing nine-and-a-half lengths clear of Dynamite Dollars. 

Like his stablemate Greaneteen, Politologue also won the Tingle Creek in 2020 but has failed to register a win in three starts since. 

He was due to defend his Queen Mother title last year but had to pull out moments before the race after connections discovered blood in his nose. 

Nicholls concedes it will be hard for him to win against younger rivals and says it could prove to be a swansong. 

He added: "He won the race two years ago and he's a dual Tingle Creek winner. He's 11 now, so he's got it all to do — there's a lot younger legs in the race. It's going to be hard for him. 

"I suspect this will be his last run or second-last run — we may go on to Sandown and run him. 

"He's been an amazing horse. I think this will be the sixth time he's run at the Festival, so he's been fantastic and I wouldn't mind a few more like him."