The City boss has decided to give the ex-Liverpool striker another chance in tomorrow's UEFA Cup first round tie and Fowler will be well aware that his chances are running out.
"The time has come for Robbie to show what he can do," said Keegan.
"I have defended him in the past because there was a reason to. When he came here, he hadn't played for a long time and he had just come back from a major injury.
"We know what he can do and if he does it, we all know he is world class. He has an opportunity to show that against Lokeren."
Keegan claims he wants to rest Wanchope for the home game with managerless Tottenham - we will know for sure on Sunday if the Costa Rican has been rested or dropped. If the latter then it is certain he will not be best pleased.
Michael Tarnat is unlikely to feature as he is still suffering from the thigh strain that kept him out at Fulham. Danny Tiatto will step in again, leaving a spot in the squad for promising youngster, Stephen Jordan.
As for the Belgians, they have picked up just 2 points from 6 games this season and lie bottom but Keegan insists City will approach the game just as they did in the preliminary round.
"We have spoken to people we respect who say they are capable of playing well and scoring goals," he said.
"I expect they will adopt the same stubborn attitude that TNS did in the previous round but this team is better, come from a stronger league and the tie will be tougher.
"Having said that, I would be very disappointed if we didn't go through because I am convinced we have a chance of winning this competition.
"If we are going to get knocked out, I want it to be against a real top-class side but as we get further down the line, I really think we are equipped to take on the very best."