In a statement the club said Al Wasl had made an improved offer after Atletico Madrid had rejected the initial bid.
"Forlan was expected to visit Dubai this week to negotiate personal terms with Al Wasl but the club has confirmed that Forlan's visit has been postponed while they wait on Atletico Madrid's reply," it said.
Forlan, 32, voted player of the World Cup finals in South Africa last year, has struggled for form in recent months in Spain's La Liga after reports of a rift with former Atletico Madrid coach Quique Sanchez Flores.
Al Wasl chief executive Ashraf Ahmad Mohammad earlier told Gulf News that the club was striving to make Forlan Maradona's first foreign marquee sign.
"He (Forlan) is one of the big names on the line...we are working on it. We are certainly doing our best to bring top things to this country, because the UAE (United Arab Emirates) deserves it," Mohammad was quoted as saying.
Maradona, who captained Argentina to their 1986 World Cup triumph, takes charge of the seven-times UAE league winners next month.
Mohammed said Maradona had already told the club where their weaknesses lay after watching videos of their matches.
"He knows that we've signed Chilean midfielder Edson Puch, and he's seen Francisco Yeste and Mohammad Shaiba," he said.
"He's now talking about a striker and I think that we've given him that opportunity."
