Less than 24 hours after Manly great Daly Cherry-Evans sank the boot into the Sea Eagles at Brookvale, Seibold was called into a meeting on Friday evening.
He was told by chairman Scott Penn and CEO Jason King he would be sacked with 20 months left on his contract, as Manly begin searching for a successor.
It was Cherry-Evans' announcement last March that he was leaving Manly that kicked off a 12-month spiral for the Sea Eagles, falling from contenders to outside the finals.
And ultimately it was his return and the Sydney Roosters' 33-16 win on Thursday night that proved the final straw.
Seibold had been under pressure from midway through last season, when Manly fell out of the eight with successive losses to the lowly-ranked Newcastle and Gold Coast.
At the time Manly officials felt there could be mitigating factors, including injuries and the Cherry-Evans saga, and opted to give Seibold more time to turn it around.
The 51-year-old was told in off-season meetings that things needed to change and the in-game capitulations had to stop.
But ultimately Manly's 0-3 start failed to convince officials that history was not repeating, with bosses acting now to try to save the Sea Eagles' ailing season.
The capitulations were there again in the round-one golden-point loss to the Raiders, before serious questions were raised following a 36-16 loss to Newcastle.
Seibold had looked in serious trouble from late in Thursday night's loss, when fans went from playfully booing Cherry-Evans to chanting "Seibold out".
Ultimately, it took less than a day for them to be granted their wish, with assistant coach Kieran Foran admitting on Friday night he was stunned by the news.
"I'm shocked. (Just) shocked," Foran said on Fox League's coverage of Friday's games.
"It was business as usual for us this morning.
"A disappointing loss last night, but we were in there this morning with Seibs going through the review of last night's game and preparing for Sunday's training."
Manly have Foran and Jim Dymock as assistant coaches who could take over in an interim capacity. Brett Kimmorley is NSW Cup coach and could also be considered.
One coach they can't look at long term is Willie Peters, who this week agreed to take on the new PNG NRL franchise.
It's understood Manly had spoken to Peters in the past.
Brad Arthur would be one option after being an assistant at Manly in 2013, when current CEO Jason King was part of a side that made the grand final.
Matt Ballin is another, and would carry favour with the club's old boys. He is currently an assistant at Brisbane.
Michael Ennis looms as another potential candidate, having been viewed as Seibold's long-term replacement as recently as last year while serving on the coaching staff.
Seibold took over from Des Hasler as Manly coach in 2023, leading the Sea Eagles to the second week of the finals the following year.
At the end of 2024 he was handed an extension for the 2026 and 2027 seasons, but has now been axed just three games into that new contract.
In just over three years at the club, Seibold had a 48 per cent winning rate with 37 wins, 38 losses and two draws.
Seibold is the first coach to be sacked this early in a season since Jason Taylor at Wests TIgers in 2017.
Asked about the pressure surrounding his position after Thursday night's loss, Seibold had been hopeful he was still the right man for the job.
"I can't control that decision," Seibold said, when asked about his future.
"Only (chairman) Scott (Penn) and the ownership group can control that, so there's no point me wasting any energy or time on that.
"I've invested a lot of time in the club over the last three and a bit years and made a lot of sacrifice with my time.
"But if I'm not the right person, I'm sure Scott will tell me."
The Sea Eagles' first post-Seibold game is against the Dolphins at Redcliffe on Thursday night.
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