Daily Telegraph rugby league writer David Riccio tweeted: "The replacement for Seibold will be made at a later date, in the interim, I understand @brisbanebroncos assistant coach Peter Gentle will steer the Broncos for the remainder of the season."
While Seibold has repeatedly said this year he wouldn't quit, his position became untenable as the flagship NRL club slumped to its lowest ever ebb.
Sitting second-last on the ladder, the Broncos have won just three games all year — and only once since the season restarted in May after the coronavirus-enforced suspension.
Seibold's departure comes after the Broncos' biggest private shareholder Phil Murphy told Nine News: "It's like having a cancer and it has not been cut out … if you don't treat the cancer you die and that's what, unfortunately and sadly, I don't want to see the Broncos die."
An angry Seibold hit back at those comments.
"I have only met him three times in my life and two of those were in the changerooms after games when the players complained about him," Seibold told The Australian.
"He is not a decision-maker at our club. I think it is a pretty insensitive comment in regards to people who have to go through that ordeal.
"I find it disgusting from a person who has no understanding or knowledge of our inner sanctum."
Speculation had intensified in recent days Seibold was on the way out, as reports emerged he had been offered a million-dollar payout to leave just two years into his five-year deal.
Signed to take over from Wayne Bennett in 2019, the Broncos have lurched from one disaster to the next under Seibold's tenure.
Biosecurity breaches by players and staff and reports of a divided dressing room have hurt the club, while Seibold has endured personal trauma to go with his professional pain.
The former South Sydney mentor was forced into self-isolation for two weeks after staying in Sydney to deal with a "serious" family matter after the Round 13 loss to the Rabbitohs, and he has since hired lawyers and cybersecurity experts after vile rumours were spread about him online.
Brisbane legend Kevin Walters is the hot favourite to take over from Seibold, but yesterday denied he'd had any contact with the Broncos about taking charge.
Darius Boyd will retire at the end of the year and threw his support behind the Queensland coach to turn the Broncos around.
"Kevvie's resume speaks for itself," Boyd told Nine's 100% Footy.
"He won five premierships at the Broncos and he's coached at different levels and been an assistant at the Broncos and Melbourne.
"If that was the case (taking over as coach), the way the Broncos went, I'm sure the fans and everyone in rugby league would get behind him."
Channel 9's Danny Weidler reported today Walters has already been in contact with Broncos players about his possible arrival at Red Hill.
"The mail is increasing that Kevvie Walters is a very good chance of getting it," Weidler told the Big Sports Breakfast.
"In fact people will tell you he's already been speaking to Brisbane players about his potential arrival at the Broncos.
"Players are happy to say that they've heard from Kevvie Walters."
