The USA could be without No.8 Rob Lumkong for their opening match against the Irish on Saturday
Lumkong has a bruised right knee and will undergo a fitness test shortly before the kick-off.
27 times capped Lumkong is one of the most experienced players in the USA line-up, and would be a big loss were he to pull out. It he does fail the fitness test the pack is likely to be reshuffled with Dan Lyle possibly moving to no.8, Dave Hodges to the flank and Alex Parker being recalled in the second row.
USA coach Jack Clark discounted suggestions that they had targeted Ireland as the pool opponents who they could defeat. "Romania remains our target in that regard", he said. "Even if we turned the rugby world on its head by defeating Ireland on Saturday, Romania would still be our principal target.
"But we believe that our mostly amateur players are capable of giving these professionals a real run for their money. We won't be lacking in spirit and determination on Saturday", said Clark.