Simoes wants to open training camp for domestic players on Tuesday, but two clubs, Saprissa and Cartagines, reportedly don't want to release players for two weeks to the national team.
Following Wednesday's surprise loss to the Columbus Crew, Saprissa is in danger of not qualifying for the knockout stage of the Concacaf Champions League.
Simoes insists he can get the job done.
"With 12 points," he said, "Costa Rica is very strong." He was referring to the 12 points in the Ticos' first five games (four wins and one loss). They have since lost to Honduras (4-0), Mexico (3-0) and El Salvador (1-0) and dropped to fourth place.
"Costa Rica sí puede," he said. ("Costa Rica can do it.")
"I'm very happy to coach Costa Rica," Simoes added. "I know its soccer. I've been in touch with what has been going on, and I'm a friend of Alexandre Guimaraes."
Guimaraes, Simoes' countryman, coached Costa Rica at the World Cup finals in 2002 and 2006.
Simoes is familiar with Concacaf teams, having coached Jamaica twice and Trinidad & Tobago.
He led the Reggae Boyz to the World Cup finals for the first time when they finished in the top three in 1997 Hexagonal. One of Jamaica's key results was a 1-1 tie with the USA at Washington's RFK Stadium.
Costa Rica will need a win on Oct. 14 at RFK to have any chance of overtaking the USA for one of the three automatic berths in the World Cup finals.
It currently holds a four-point lead over El Salvador in the battle for fourth place. Concacaf's No. 4 team will advance to a playoff against South America's No. 5 team for a berth in the finals.
Simoes also coached the Brazilian women's national team to the silver medal at the 2004 Olympics and coached three Brazilian teams earlier this year.
He handed in his resignation after officials of Portuguesa came into the locker room with guns on their belts and threatened the players after a loss.