Ireland captain Rory Best must shake off a stomach bug if he is to face Italy in Rome in Saturday's Six Nations showdown.
Hooker Best missed Ireland's captain's run at the Stadio Olimpico on Friday, instead remaining at the team hotel in a bid to beat his illness.
Niall Scannell would start should Best fail to recover, with James Tracy likely to fly out to join the squad as cover.
Ireland remain confident Best will be fit to start, and could leave a decision on their skipper's fitness until Saturday morning.
"Rory has had a bit of a stomach upset overnight, he didn't sleep particularly well," said forwards coach Simon Easterby.