Endacott is midway through a two-year contract, but that deal lapses if the club drops out of Super League. With the candidates for promotion now looking likely to meet the competition's criteria, he has conceded that the game is up and is set to return to New Zealand.
"I've booked the flight," he said. "I was holding off and holding off but then I thought that I was just kidding myself. I would say that barring a miracle this would be our last match."
The former Wigan and New Zealand Test coach insists that he has enjoyed his latest foray into the British game and that he has not ruled out coaching again in the future. "The only thing I haven't enjoyed has been the results," he said.
Widnes will now move to fill the vacancy in time to plan for next season's push to regain their status. Wigan's assistant coach, Denis Betts, is one who has already been linked with the job.
For his last game Endacott will be without two of his stalwarts, Mick Cassidy and Mark Smith, who needs an operation on his wrist.
Better long-term news for the club is that one of their more promising younger players, the 19-year-old forward Steve Nash has agreed to stay on despite interest from Leeds, Bradford and Warrington. "I was flattered to receive offers from such big clubs, but I'm glad I've been able to stay at Widnes," he said.
Wigan's injury problems are, meanwhile, pursuing them right to the end of the season, with two players, David Vaealiki and Martin Aspinwall, needing knee operations. Both are expected to be fit for the start of next season, by which time Aspinwall will be a Huddersfield player.
Chris Ashton, with just one first-team appearance behind him, has been drafted in for Sunday's match at Huddersfield.
Wigan and Terry Newton are discussing whether to appeal against the Super League record 10-game suspension which he was given this week.
Ali Lauitiiti has extended his contract at Leeds to keep him there until the end of the 2008 season. Warrington have released their former Wigan and Halifax full-back Daryl Cardiss.