On-loan Bournemouth midfielder will return to parent club Norwich City next season after the Cherries decided against making the move permanent.
The 24-year-old made just eight Premier League appearances for the Canaries this season before falling out with previous manager Daniel Farke.
This prompted Championship side Bournemouth to swoop in and take the midfielder on loan until the end of the season, with an option to buy Cantwell permanently for around £11m included within the deal.
However, current Norwich boss Dean Smith confirmed on Friday that Bournemouth have opted against a permanent deal, meaning Cantwell will return to Carrow Road ahead of the 2022-23 Championship campaign as things stand.
Speaking ahead of Norwich's final game of the season at home to Tottenham Hotspur on Sunday, Smith said: "I envisage him being back with us in pre-season. Bournemouth have not taken the option on Todd, so Todd is back as a Norwich City player."
Scott Parker's Bournemouth finished second in the Championship this year, meaning they will swap divisions with Norwich and return to the Premier League following a two-year absence.
Cantwell appeared just 11 times in the league under Parker since his January arrival at the Vitality Stadium though, in which he failed to find the back of the net during his stay.
