Malbranque, 30, was taken to hospital on the south coast after collapsing on the pitch during the first half of his side's 1-1 Barclays Premier League draw at Fratton Park.

However, he was released after checks and allowed to fly back to the north east the same night.

The Black Cats' physician Dr Glen Rae told the club's official website, www.safc.co.uk: "Steed has a musculo-skeletal chest problem for which he is receiving treatment.

"We are very grateful for the help of Portsmouth medical team, paramedics and Portsmouth local hospital for their help on Tuesday for arranging appropriate investigations for us."