Ireland are sweating over the fitness of winger Andrew Trimble, who is struggling after picking up an injury against Wales.
The Ulster speedster has endured an injury-disrupted season and was forced off with a foot problem just 35 minutes into Saturday's win in Cardiff.
He required a scan on the problem, but after that proved inconclusive, he was ruled out of the second warm-up game against Scotland as he undergoes a further scan to diagnose the issue.
Trimble has spent much of the season on the sidelines with a foot problem, and this latest set-back could prove fatal to his hopes of making Ireland's World Cup spot.
"(The initial scan) was a little bit inconclusive. He is going for another scan tomorrow. Until we see what the result of that scan is we can’t really give you any further information," said kicking coach Richie Murphy.
"It is a source of concern because he has a sore foot. We’ll have to see where that is at.
"The doc is trying to work away on that stuff at the moment," added Murphy. "He can’t give us any more information than I’ve actually given you, so we need to get it rescanned and see if that comes up with a clearer picture."