Dube spent last season on loan at Siwelele from the Bucs, making nine starts as the Free State club ended the campaign in 11th spot.
The former Royal Eagles defender however joins a number of players including Thembinkosi Lorch and Gladwin Shitolo who have been re-called by the Soweto giants, where they will be assessed by new coach Muhsin Ertugral when the squad reports for pre-season training tomorrow.
Celtic CEO Khumbulani Konco has confirmed that Dube has gone back to Gauteng, adding that his club may still make a move for his return to the City of Roses.
"He has gone back to Pirates,” Konco tells snl24.com/kickoff. "We are still interested in keeping him next season and we will send a request to Pirates,” he added.
Celtic today revealed a number of new signings at the club, including Cheslyn Jampies, Dean Hotto, Atusaye Nyondo, Mpho Maruping, Sibusiso Mxoyana, Tlou Molekwane and Khethokwakhe Masuku.