Estrada, 21, who has three senior caps for Costa Rica, is expected to arrive in Australia next week but the deal is not complete yet with paperwork to be done, according to the Adelaide Advertiser.

The Costa Rican's arrival also means the Reds will have seven imports on their books, which is two more than the permitted A-League quota of five.

New Dutch signing Andwele Slory, though, falls outside that quota as he's a guest player, while it is understood Brazilian full-back Cassio may soon qualify for Australian citizenship, to allow Estrada to fit under the quota.

Speaking about Estrada, Griffin said: "He played against Daniel Mullen in the Under-20 FIFA World Cup finals last year. He is impressive."

Estrada was linked with Portuguese giants Benfica and Sporting Lisbon after playing a key role at the 2009 Under-20 World Cup finals in Egypt, helping Costa Rica qualify for the semi-finals after knocking out Australia at the group stage.

It is understood the Reds hope Estrada, an attacking midfielder, will complement Argentine number 10 Marcos Flores in the centre of the park.