Dolphins forward Tom Gilbert has suffered a major setback in his recovery from a torn anterior cruciate ligament after a blood clot prevented him going under the knife.

The 23-year-old ruptured his ACL in February's pre-season trial against the Warriors.

The team flew home the next day, with Gilbert developing a blood clot in his calf that later transferred to his lung.

He has since recovered, but the development led to his surgery being postponed.

The Queensland forward will now be racing the clock to be fit for the start of the 2025 season, with rehabilitation from ACL surgery usually in the nine-to-12 month region.

Dolphins coach Wayne Bennett confirmed the setback, but could not put a timeline on the player's surgery.

"I can tell you what we know, and what we know is there's no definitive conclusion about when the operation's going to be," Bennett said after Sunday's season-opening defeat to North Queensland.

"He did have a blood clot and it's been resolved.

"There's an ongoing examination with the doctor and we don't have a definitive answer about what's going to happen.

"We're not going to speculate.

"He was never going to play this season anyway and no one was rushing around to get him an operation."

Gilbert sat on the Dolphins bench and watched the 43-18 opening-round loss to the Cowboys at Suncorp Stadium.

Bennett reiterated the champion lock would pull through.

"It's no more serious than the day he injured his leg," Bennett said.

"He's OK. He's here today, he's fine. He's young and has still got opportunity in front of him.

"You don't put your footy boots on thinking (injury) won't happen to you. He is a strong person with a great club around him."