Chelsea midfielder Mikel's father abducted
The 24-year-old Nigeria international played in Sunday's season-opening 0-0 draw at Stoke City despite knowing his father Michael was abducted on Friday.
In an interview with Sky Sports News, Mikel said: "We haven't heard anything, no phone calls, nothing.
"Whoever has got my dad or knows where my dad is please contact me and hopefully he will be released. Please let him go - my dad is an old man and he hasn't done any harm to anyone as far as I know and I don't know why he has been taken.
"This happens a lot, not in the northern part of Nigeria but in the eastern part. It's a very safe place where we live in Jos, I think it's a first that my father has been taken in the northern part," the midfielder added.
His father's house in Jos was abandoned and the local police told Reuters they were investigating the disappearance but most of the local law enforcement were focused on dealing with a burst of religious unrest in the region.
At least 10 people were killed on Monday in the area around Jos when Christian and Muslim youths and the military clashed, local officials said.
Jos lies in the central "Middle Belt" of Africa's most populous nation, where the largely-Christian south meets the mostly-Muslim north, and has often been the scene of deadly religious violence.
Mikel, who has never managed a Premier League goal for Chelsea, came close to scoring against Stoke with a long-range volley that goalkeeper Asmir Begovic tipped over the crossbar.
"It was really difficult. I spoke to the manager [Andre Villas-Boas] who asked me if I wanted to play the game and I said I wanted to play," explained Mikel, who joined Chelsea in 2006 and won a league winner's medal last year.
"I didn't want to let my team down or the club down or my family. If I didn't play I think my mum would have been very sad with me.
"I've told some of my team-mates today but most of them didn't know on Sunday. I didn't want everyone coming up to me saying 'oh sorry Mikel', I just wanted to get on with the game."
Chelsea's young player of the year in 2007 said everyone back home knows he is a professional footballer.
"We live in a very safe and secure place in Nigeria so this is a real shock to me," said Mikel. "Me and my brother [in England] still cannot believe it.
"I don't know what to do at this point. It is very difficult for me."
Mikel said he would like to return to Nigeria but had been advised on safety and security grounds to remain in England.
Earlier, his management company The Sport Entertainment & Media Group said no ransom demand had yet been received from the kidnappers.
Chelsea said in a statement: "We will give Mikel and his family our full support at this most difficult time."
It is not the first time a relative of a Premier League player has been abducted in Nigeria after former Everton defender Joseph Yobo's brother was kidnapped in 2008.
Kidnapping of oil workers in the southern Niger Delta has been relatively common in the past but abductions have begun spreading further north.