After claiming a third-straight premiership, Fagan confirmed on Thursday he wouldn't complete his contract and return for an 11th season at Springfield next year.
That caught Ashcroft, who picked up his first Merrett-Murray Medal later that night, off guard.
"It was a bit of a surprise; I thought it was maybe 50-50," the 22-year-old said after winning from 2025 victor Josh Dunkley and four-time champion Lachie Neale.
"But Fages deserves to walk into the sunset and do what he pleases.
"It was very emotional … I can't imagine what the guys who have been here 10, 11 years, felt.
"It's a selfless approach. He's looking forward to his next chapter."
Fagan's afternoon confirmation ensured the evening was a celebration of the 65-year-old's time at the club, with the coach relishing the freedom as he launched into his yearly address that's now become custom.
One by one he asked players to stand before pumping up their tyres and explaining why they were so valuable to the club, choking back tears as he completed his final address as coach.
Lachie Neale, set to move to Collingwood, was recognised for his eight-year stint at the club, but received pantomime boos from the 1000-strong audience and a cheeky pledge from teammate Josh Dunkley that he'd receive a tag when they meet next season.
Fagan had told chairman Andrew Wellington of his desire to leave weeks ago, when the Lions were beaten by Sydney to begin their AFL finals campaign.
It means the organisation has had time to consider their options on how to replace a man who helped transform the club from wooden-spooners to four-time grand finalists inside a decade.
Football manager Danny Daly and assistants Cam Bruce and Dale Morris have been spoken of as potential internal candidates.
Former Lions assistant Murray Davis, now football boss at Adelaide, Geelong coach and former Lions premiership player Chris Scott, former West Coast flag-winning coach Adam Simpson and Nathan Buckley have all been mentioned as potential outside options.
There is an expectation the Lions' leadership group will be sounded out by club hierarchy and Ashcroft knows the direction the club take will define the Lions' next chapter.
"Whether it's someone internally or a fresh face to bring new ideas," he pondered.
"I'm not sure exactly what the process is, but Cam Bruce or Danny Daly could easily step into that role.
"It is a weird sort of circumstance (taking over a team that's won three-straight titles).
"I'd imagine the leadership group will get consulted, but the club's made so many great decisions over the journey."
Whoever takes charge, it's certain Ashcroft's hunger won't subside after the two-time Norm Smith Medallist was controversially denied a third-straight honour and also overlooked for All-Australian honours.
His tongue-in-cheek response to that team-of-the-year snub raised eyebrows but helped Ashcroft find a new level on his way to the Gary Ayres Award for player of the finals.
"I had a bit of fun with it, a muck around, but I was just driven to help the club win another flag," he said.
