Atkinson, who spent two successful spells on loan at Dale last term, has been on loan with the Millers for the last month and agreed to stay at Don Valley until the end of the season.
However, after learning of Dale`s interest, he has had a change of heart and opted to join the League One side, according to the Millers.
"We are disappointed that Will has had this last-minute change of heart, but he has decided to join Rochdale where he had a successful time last season in helping them to promotion to League One," said chief operating officer Paul Douglas.
Source: PA
Source: PA