Ulster winger Jacob Stockdale limped off during the first-half of his side's Champions Cup trip away to Wasps.
Stockdale was seeing grimacing after five minutes with what looked like a leg injury. BT Rugby commentator Nick Mullins said that he was told that Stockdale had suffered a dead leg, but the manner in which the 21-year-old left the field suggests that the injury could be more serious than the initial diagnosis suggests, as his left thigh was heavily strapped when he was sitting on the bench.
Stockdale was named in Joe Schmidt's 36-man Ireland squad on Wednesday as one of 16 backs.
The Ulster flier will face stiff competition for a place on the wing with Keith Earls, Andrew Conway, Fergus McFadden and Jordan Larmour also named in the squad, but he will also now face a battle for fitness as Ireland kick off their Six Nations campaign in Paris in 13 days time.
Stockdale has enjoyed a stellar campaign in Belfast this season with eight tries in 12 appearances. He was also Ireland's breakout star during the November internationals scoring tries against South Africa and a brace against Argentina.
