England star Ben Te'o is "touch and go" to play for Worcester Warriors in Sunday's key Premiership game at leaders Wasps.
The 30-year-old centre was led from the pitch at the Aviva Stadium after sustaining a head injury during England's 13-9 defeat to Ireland in Saturday's Six Nations clash.
"I'm following concussion protocols," Te'o told BBC Hereford & Worcester. "I need to get back out there as soon as I'm fit and ready, but this week will be touch and go."
Te'o has won eight caps for England this season, playing for Eddie Jones' side twice more than he has played Premiership matches for Worcester.
The replacement came on in the 63rd minute in Dublin but was soon heading back to the bench after suffering his second concussion of the season - the first one ruled him out of England's autumn internationals.
Worcester will be keen to get the Kiwi rugby league convert back in their line-up as the 11th-placed Warriors are seven points clear of bottom club Bristol with five Premiership games to go.