Wales skipper Sam Warburton is to undergo a scan on Monday to determine the extent of damage caused following a clash of heads with Josh van der Flier.
The 27-year-old was forced off the field in the opening 40 minutes of Cardiff Blues' 16-13 defeat to Leinster on Saturday evening due to a heavy blow to the face.
Warburton could be a doubt for Wales's autumn international series should it be confirmed that he has suffered a fracture, with an eight-week layoff likely if that is the case.
The Dragons are already facing the prospect of losing Taulupe Faletau for their upcoming friendlies because of knee ligament damage suffered by the 25-year-old.
