Long-serving midfielder Mikel is yet to make an appearance for the Blues this season and has been linked with a move away from Stamford Bridge.
The 29-year-old missed the start of the campaign under new boss Antonio Conte to represent Nigeria at the Olympic Games and has failed to work his way back into favour.
Super Eagles boss Gernot Rohr claims Mikel is in ‘advanced’ talks with French club Marseille.
“I think he must seek a new challenge elsewhere so he can enjoy his football”
And former Bolton star Okocha believes he needs a fresh start.
“In my personal view I think he must seek a new challenge elsewhere so he can enjoy his football,” Okocha told FootballGhana.
“What he is going through at the moment is the worse thing that could happen to a player and I urge him to move on.”
Mikel, who joined Chelsea in 2006, is out of contract at the end of the season.
He is unlikely to be offered an extension and Conte recently admitted he is unsure about his future.
The Blues boss said: “The situation with Obi Mikel is simple: he’s in the squad. He stays with us.
“We know that, at the end of the season, probably his contract will expire. But I don’t know what happens now.
“He’s a player who is part of this squad and every single game I take my decision about him.”