Cesar Menotti says Argentina must move quickly to appoint a new coach and avoid a dangerous situation in qualification for the 2018 World Cup.
Argentina are without a manager after Edgardo Bauza was removed from his post earlier this month following a run of just three wins in his opening eight matches.
The first game of Messi's ban saw Argentina lose 2-0 to Bolivia in what proved to be Bauza's final game in charge.
Writing in Spanish publication Sport, Menotti said: "It seems to me that the AFA [Argentine Football Association] has a great urgency to decide who will be the new coach. And a month more, a month less in this instance is very important.
"If you lose to Uruguay in qualifying in August, whoever is the coach, the situation is going to be dangerous."
"I would like the coach who arrives to have projects. But nothing is known. Once again the leaders move in the shadows. There is no clarity," Menotti added.
"You really do not understand anything. It is not understood if they spoke or did not speak with Jorge Sampaoli.
"The main thing must be that those responsible for the appointment say what style of coach they are looking for, what project. They cannot say they did not talk to anyone.
"When not working with an open face these things happen. The selection needs serious, quick debate."
