The former England international's contract at Goodison Park expired during the summer, but he has continued to train with the club in a bid to return to full fitness.
Alli has recently been linked with a move to Serie A new boys Como, managed by former Arsenal and Chelsea midfielder Cesc Fabregas.
The 28-year-old has further fuelled talk of a switch to Italy by announcing his Everton exit in an Instagram post on Friday.
In the post, he sent his sincere thanks to Everton, their staff, players and fans for supporting him in his bid to return to football, despite not officially being on their books.
It read: "As widely published this week, 2025 may set me on a new path with some exciting opportunities.
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"Before any of that happens it's very important for me to make clear how grateful I am of all the fans, staff and players at Everton FC for the support they have given me.
"It's been an incredibly tough journey trying to put the final pieces together to regain match fitness and I cannot thank the Everton staff enough for the hard work they have put into this process.
"Unfortunately, things haven't worked out as we all would have hoped and I think it's the right time for me to turn a new page.
"I want to wish everyone at this amazing club the very best of luck and hopefully we will see each other again soon."
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The attacking midfielder was one of English football's brightest talents when he burst onto the scene at Tottenham in the 2015/16 season.
He went on to spend seven years in north London, registering 67 goals and 58 assists in 269 appearances across all competitions.
Alli was a permanent fixture under then boss Mauricio Pochettino and was named in the starting line up for the 2019 Champions League final defeat to Liverpool.
But things quickly turned sour for Alli after falling out of favour at Spurs leading to his transfer to Everton.
Injuries hampered his time at Goodison Park and an ill-fated loan spell at Turkish giants Besiktas did little to aid his return to form.
The 28-year-old later revealed in an interview that he became addicted to sleeping pills following his spell in Turkey and bravely opened up about his difficult childhood.
Alli recently revealed his aim of making a blockbuster comeback and is targeting a return to the England squad ahead of the 2026 World Cup.
Fabregas could be a key figure in helping Alli realise his dream by luring him to Como where the Spaniard also holds a position as minority shareholder.
The former Tottenham star was spotted in the stands at Como alongside a host of Hollywood stars such as Keira Knightley, Adrien Brody and Michael Fassbender during Como's 2-0 win over Roma last Sunday.
Asked about the possibility of Alli rocking up at Como, Fabregas said: "I got to know him yesterday.
"I don't want to talk much about this, but perhaps there's a chance that he will start training with us after Christmas.
"Let's see. It would be to help him get in shape and nothing more.
"For now, we must enjoy this night. We must talk about Como, Gabrielloni and the lads. This is the most important thing."
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