Former Real Madrid goalkeeper Iker Casillas is in hospital after suffering a suspected heart attack while training with Porto, according to reports in Portugal.
The 167-time capped Spain international goalkeeper, who turns 38 later this month, only signed a new deal with the Portuguese club in March.
Casillas has been with Porto since 2015, having spent the entirety of his career until that point with Real Madrid, and has impressed this season as the side aim to retain their Primeira Liga title.
Porto are currently second in the table, two points behind Benfica with three games remaining as well as a cup final clash against Sporting Lisbon scheduled for May 25.
The side were also knocked out of the Champions League 6-1 on aggregate by Liverpool in the quarter-final stage last month.
However, as well as winning the Champions League three times while at the Bernabeu, he also became the goalkeeper with the most penalty saves in the competition when he kept out a spot-kick from Lokomotiv Moscow’s Manuel Fernandes for Porto during a group-stage encounter.