Brendan Rodgers says "change is needed" to Celtic's squad this summer to guard against the complacency that has crept into his side in recent weeks with such a comfortable lead in the Scottish title race.
"It's either that or the manager goes," the Northern Irishman said as he indicated his preference to make changes to his playing staff.
Rodgers was left angry by Sunday's defeat by bottom side St Johnstone, a result that means they cannot now clinch the title at home to Kilmarnock on Saturday despite their 13-point lead over Rangers.
After losing just twice in the whole of 2024 in all competitions - to Rangers and Borussia Dortmund - Celtic have suffered six defeats so far this year.
"We always want to improve the team, improve the hunger in the team," Rodgers said. "Because one of the ways to succeed and guard across what I've been talking about, is you need the freshness.
"It's either that or the manager goes. It's as simple as that. You cannot be at a club for a long period of time with the same group of players.
"And, likewise, the same group of players need a different voice maybe. But, at this moment, it will be about improving the squad."
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Changes were already certain, with Celtic having failed to replace Kyogo Furuhashi when the striker left for Rennes in January.
Meanwhile, Kieran Tierney has signed a pre-contract to return from Arsenal as fellow Scotland left-back Greg Taylor looks poised to exit on freedom of contract.
"I think naturally what you have at our club, there is a natural slide of players that move out and come in every three or four years," Rodgers said.
"I think change is needed. That freshness, that new energy coming into your squad that alleviates any of that sort of complacency. However this team does at the end of the season, we want to improve it. The team needs the competition."
Rodgers expects a positive reaction after claiming in Perth that there was a "comfort" in his team that he did not like.
"There's no doubt that the gap in the league, and also maybe a little bit of coming out of the Champions League, has just taken a slight edge off," he added.
"So that's a mindset that I need to continue to work within the squad in order to improve that. I don't forget how well they have done, but I can't accept what that was last week."
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