It follows a week in which both Porto and Madrid won their respective league titles, with Casillas expected to officially announce his retirement from football at the end of the campaign.
The goalkeeper left Madrid in the summer of 2015 and as Marca highlight, that was following an acrimonious fallout with Perez whereby he was allowed to leave the Spanish giants ‘through the back door’.
However, that now appears to be water under the bridge with Casillas – the player with the second most games in the club’s history (725) – now due to return to the Spanish capital.
Last month, Casillas announced he was withdrawing from the Spanish FA presidential elections having been due to stand against the current incumbent Luis Rubiales.
In May last year, the goalkeeper fell ill during training with Porto and was rushed to hospital where he underwent emergency surgery.
Whilst that was a success and Casillas was discharged five days later, it had appeared unlikely that he would return to first-team football but despite training this season, he has not played any first-team games.
Casillas is one of the most decorated players in Spain’s history, playing over 700 games for Madrid before joining Porto in 2015.
He won three Champions Leagues with the capital giants, as well as two European Championships and a World Cup in his 167 caps for La Roja.