The Millers had offered the versatile 27-year-old a new contract to replace the deal that extends at the end of the month, but Odoffin has now told them he will not be taking it up.
Odoffin made over 100 appearances for the club in a variety of positions after joining from Hamilton Academical.
Boss Matt Hamshaw told the Yorkshire Post
“We’re really disappointed that Haks sees his future away from The Millers but we also understand it for all the reasons he has detailed in the many discussions we have had about his future,"
“With the chairman’s backing and his own desire to try and retain the player’s services, we can rest assured that we tabled an offer and negotiated to a point which we felt as a football club represented how highly we think of Haks. A player of his talents will understandably have enticing offers elsewhere and his performances have been so good for a long time now that we absolutely don’t begrudge him that.
“He has been first class for this football club both as a player and an ambassador in the community and I am 100 per cent confident that you won’t find anybody who has encountered him throughout the last four years that says otherwise. Haks has been a big a champion in the community as he has a winner on the pitch.
“On behalf of all the players he has played alongside and the staff and supporters that he has represented, I want to say a huge thank you to him.
“I want to make it explicitly clear that while we saw a big future for Haks here, he leaves the club with our sincere best wishes for whatever comes next.
“We’re grateful too, that he has informed us of his decision early and been honest and transparent with us throughout the process.