Chelsea midfielder John Mikel Obi has appealled for the return of his father, who has been abducted in Nigeria.Michael Obi has not been seen or heard from since he failed to return home from work on Friday in Jos."John Mikel Obi's father was abducted in Nigeria on Friday," SEM Group said on Twitter."I've always tried to help the country, this is the time for the country to help me, whoever knows where my dad is should please contact me," Mikel said.The player was told before Sunday's Premier League game between Chelsea and Stoke City, but decided to play."I said I would like to play, I wouldn't want to let the club down and if I didn't play that game. I think my mum would be very sad, she told me to go out there and be strong and make sure I do well in the game," the 24-year-old told Sky Sports News."I don't think my team-mates know, I told [Didier] Drogba today [Monday] and [Salomon] Kalou who is a good friend, I didn't want everyone coming up and saying sorry."SEM said no ransom demand had yet been received but Mikel admitted his father's famous son was likely to be known by any potential kidnappers."I think they do know, my family have lived there all their lives so they will know who he is and who I am," he said."This happens a lot in the eastern part of Nigeria but my dad would probably be the first this has happened to in the northern part which is a very safe place, this is very rare and is surprising everyone."His family told the BBC that they have had no contact with Obi senior but believe he is "safe and well".The Chelsea player's agent John Ola Shittu said that everybody in the family remains hopeful."It's been tough for the young man," Shittu said. "The family in Jos reported him missing at the police station as expected but we're taking all necessary measures to find him. We've told him to be brave and to stay calm."Shittu said the family has also not heard from anyone claiming to hold Obi senior.Kidnappings - more often of oil workers, the rich and famous - are a common occurrence in Nigeria.Footballers and their families are increasingly being targetted.In July 2008, the elder brother of Nigerian and Everton defender Joseph Yobo was seized in Port Harcourt, where kidnappings for ransom are most frequent.It was not clear if a ransom was paid but Nornu Yobo was released after being held for almost two weeks.