Former Gent striker Ruiz has already admitted he would be open to the prospect of returning to the Belgian Jupiler League.
However, Anderlecht general manager Herman van Holsbeeck has admitted that whilst they like Costa Rican Ruiz, he is not their first option, which appears to be Defour.
"He is on our list. Ruiz is a good player, but not our first choice," he told Het Laatste Nieuws.
"I have a plan A, a plan B and a plan C and I'm happy my plan A hasn't been leaked yet.
"Of course we know Ruiz's qualities. We have made a list of players who will go to the World Cup, but aren't playing regularly. Ruiz is on it, but so are others."
Defour does appear to be Anderlecht's first choice, although he is believed to be a target for a number of Premier League clubs.
But Van Holsbeeck added: "Anderlecht will be a good option for him.
"Let's say he joins Fulham, then he will have to settle again.
"At Anderlecht he will be the star. If he wants to be sure of his place in the Belgian World Cup squad, then we are a perfect option. Steven is an intelligent guy. I think he knows this."