(CNN) -- Chelsea midfielder John Obi Mikel has made an emotional appeal after his father was abducted in his native Nigeria.
"Please just let him go," he told Sky Sports News.
"He's just an old man, he hasn't done any harm to anyone as far as I know and I don't know why he has been taken."
Michael Obi, who runs a transport company in Jos, the main city in Plateau State in central Nigeria, has not been seen or heard of since he failed to return home from work last Friday.
Obi Mikel was told of the problem just before the start of Chelsea's Premier League match at Stoke Sunday which finished goalless and said his father was at the forefront of his thoughts throughout the match.
"Nigeria is the country I am from, I've always tried to help my country in any way I can, playing for my country or anything," he said.
"This is a time where I need the country to help me. Whoever has got my dad, whoever knows where my dad is, please contact me and hopefully he can be released."
Chelsea have given Mikel their support in a statement on their official website.
"Everyone at Chelsea Football Club was very concerned to hear that John Mikel Obi's father has been reported as missing and possibly abducted.
"We will give Mikel and his family our full support at this most difficult time."
Mikel confirmed they had not heard from his father's abductors and no ransom had yet been demanded.
He expressed surprise that it had happened in the region of Nigeria where he hailed.
"I think this happens a lot in the eastern part of Nigeria, but I think my dad will be the first this happened to in the north," he said.
"It's a very safe place where I live. That's why they live there."
Mikel's plight is similar to that of fellow Nigerian international, the Everton defender Joseph Yobo, whose elder brother was kidnapped in Port Harcourt in 2008.
Nornu Yobo was released after 10 days, but it was unclear if any financial demands had been met.
Obi Mikel has been at Chelsea since 2006 and helped them to the EPL and FA Cup double in the 2009-10 season. He has played 30 times for the Nigeria national team.