Luke Marshall has emerged as a doubt for Ireland's second Test against Argentina this weekend.

The Ulster centre suffered another head injury during last Saturday's opening Test against the Pumas, although it has not been diagnosed as a concussion.

The IRFU say that their medical staff are taking extra precautions with Marshall this week in the wake of the series of concussions that he suffered last season, but he has not been ruled out of playing this weekend as of yet.

Conor Murray is the other main fitness concern for head coach Joe Schmidt because of a dead leg but his half-back partner Johnny Sexton is expected to be available after shaking off a cramp to his knee.