Bundee Aki out and Peter O'Mahony on bench as Ireland make four changes for second Test with South Africa

Bundee Aki has been ruled out of Ireland's second Test with South Africa in Durban on Saturday, with head coach Andy Farrell making four changes to his side from last week's 27-20 defeat.

The centre, who had been carrying a shoulder injury during the week, is replaced in the line-up by Garry Ringrose, who partners Robbie Henshaw in midfield.

Captain Peter O'Mahony is named on the bench, with Caelan Doris skippering the team. James Ryan takes O'Mahony's place in the starting side, named at second row, while Tadhg Beirne drops into the back row at blindside flanker.

The other two changes see Rónan Kelleher and Conor Murray start as expected at hooker and scrum-half, with Dan Sheehan and Craig Casey previously ruled out.

Jamie Osborne has shaken off a groin injury to retain his place at full-back, and starts between Calvin Nash and James Lowe in the backfield.

Ringrose's arrival into the starting team sees a positional switch for Henshaw, who moves to inside centre this week. Ulster's Stuart McCloskey will provide midfield cover off the bench.

Once again it's an all-Munster half-back pairing, with Jack Crowley continuing at out-half, working alongside the experience of Murray, while Leinster's Ciarán Frawley and Connacht's Caolin Blade are the replacement options picked by Farrell.

Andrew Porter, who suffered a badly cut hand in the first Test, is able to take his place in the starting team, alongside Kelleher and Tadhg Furlong in the front row.

Farrell has swapped O'Mahony for Ryan in a bid to match some of the South African power in the pack, and Ryan joins Joe McCarthy in the engine room with Beirne in the back row, a position he has't played for Ireland since the start of the World Cup last year.

Josh van der Flier is on the