First winger George North was carried off the pitch on a stretcher during the Pro12 clash between the Scarlets and Ulster.
His injury gives Wales a worry ahead of their Six Nations fixture against Ireland next month.
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Cloud and outbreaks of rain across parts of south Wales today. Elsewhere, it'll be mostly dry with some brighter spells.
Leaders of Wales, Scotland and Northern Ireland meet in Downing Street for talks with Theresa May ahead of Britain's departure from the EU
The prime minister has offered Scotland, Wales and Northern Ireland a "direct line" to Brexit Secretary David Davis.