Porto announced on Friday they had signed Argentina goalkeeper Agustin Marchesin as a replacement for Iker Casillas, who has joined the club's coaching staff following a heart attack.

Marchesin, 31, has agreed a four-year deal at the Estadio do Dragao after completing a reported 7.2 million euro ($7.9 million) move from Mexico's Club America.

Casillas, a former Real Madrid and Spain captain, underwent emergency surgery on May 1 after suffering a cardiac arrest during training and has taken a spell away from playing as he recovers from the scare.

In a statement in July, Porto said Casillas will be the "liaison between the players, coach and management", a role that could be extended to other functions within the club.

Marchesin is Sergio Conceicao's seventh summer signing, with arrivals including Japan midfielder Shoya Nakajima and Spartak Moscow forward Ze Luis.

The new Portuguese league season begins on August 9, with Porto travelling to promoted Gil Vicente a day later.