Michael Obi, who runs a transport company, had not been seen or heard from since he failed to return home from work in Jos, the capital of Plateau State in central Nigeria, on August 12.
He is thought to have been found in Kano, 180 miles north of where he was abducted and reports in Nigeria claim his abductors have been arrested by police.
Mikel's management company SEM released a statement on Monday evening confirming that the Nigerian international's father had been released.
"SEM are delighted to confirm that earlier today [Monday] Michael Obi called his family to advise them that he had been released by his abductors," the statement read.
"SEM have waited until now to release this information, to ensure that Michael was safe. John Obi Mikel would like to thank everyone in Nigeria, his family & friends, Chelsea FC & their fans & his agents for their total support during this terrible time. A full statement of the situation will be released by SEM tomorrow [Tuesday] morning."
The statement does not reveal whether a ransom was paid.
Michael Obi is reported to have told the BBC shortly after his release: "I am very stressed."
Mikel continued to play for Chelsea during his father's disappearance, appearing in the Blues' Barclays Premier League opener at Stoke before their home 2-1 win over West Brom on Saturday.
Source: PA
Source: PA