Agbonlahor was substituted during the first half of last night's Carling Cup win over Blackburn because of problems with his calves.
But Houllier is hoping the problem is not overly serious.
He said: "Will Agbonlahor be fit for Sunday? I don't know. I'll tell you today or tomorrow.
"The most reassuring thing he said was that it is the two calves that he felt at the same time.
"If it is one calf, you might think it is a possible tear but it is the two calves so probably it involves cramp or fatigue.
"Gabby said that he had that during the home Europa League game with Rapid Vienna and then could play the following game."
Agbonlahor missed the first three games of the campaign with a calf problem.
Central defender Ciaran Clark suffered a dead leg against Blackburn although he would be unlikely to start against Wolves with the rested James Collins set to return.
Houllier said: "It's a dead leg, exactly what Stephen Ireland had on Tuesday in training. I am collecting them at the moment!
"It is a good sign because it shows we train as we play."
Collins is set to be partnered by Carlos Cuellar against Wolves with Richard Dunne unlikely to have recovered from a knee problem.