Imported galloper Grey Lion has caused his trainer Matt Cumani a few headaches.

Now Cumani hopes a gelding operation following his latest outing in December will change the stayer's attitude ahead of his latest campaign which begins in Saturday's in the Selangor Turf Club Handicap (2000m) at Caulfield.

Grey Lion came to Australia in 2016, finishing second to Qewy in the Geelong Cup before running 14th to Almandin in the Melbourne Cup.

He has 11 starts since, registering three placings, including a close second to Vengeur Masque in the Queen Elizabeth Stakes at Flemington.

Cumani originally thought wet tracks were against Grey Lion, but late last campaign he finished third on a heavy track in the Ballarat Cup.

The trainer has revised those thoughts, questioning Grey Lion's attitude, prompting the gelding operation.

"Previously he threw a lot of his races away in the pre-parade," Cumani said.

"He would walk around sweating and he'd be thinking about girls which hopefully he won't be doing this time around.

"If he does it's a bit of a miracle I think and I'll have to have a bit of a word with the surgeons."

Cumani said he could never question Grey Lion's attitude on the training track and hasn't seen any change in his form during track work since the operation.

"Hopefully he comes back a more focused, more concentrated horse," Cumani said.

Cumani has the Warrnambool Cup in mind for Grey Lion ahead of a potential trip to Brisbane for the winter carnival.

But first he will need to show his form warrants a trip.

"He's got to prove himself a better horse now that he's a gelding," Cumani said.

"He's had a couple of jump-outs and we're not going through running in shorter races like we did last time and that's purely because we're running out of time a little bit.

"We want t get him up and running and see if he's capable of running in some nicer races later in the year."