Leicester Tigers flanker Tom Croft has been called up to the England squad for the RBS 6 Nations as Stuart Lancaster assesses the impact of the weekend's European action.British and Irish Lion Croft is joined in the squad by Northampton Saints lock Christian Day while Geoff Parling’s knee and Tom Wood’s ankle are fully assessed by the England medical team.   Parling left the field in the opening minutes of Leicester’s 26-7 defeat in Ulster while Wood was replaced by Phil Dowson after 44 minutes of their 32-8 loss to Racing Metro at Franklin’s Gardens. Croft joins Tigers teammates Dan Cole, Graham Kitchener, Ben Youngs and Tom Youngs in the squad.   Meanwhile, backline trio Brad Barritt (knee), Kyle Eastmond (shoulder) and Owen Farrell (knee) are also being assessed while Luther Burrell suffered a concussion against Racing Metro and will undergo the graduated return to play protocol with a view to taking part in full training on Friday.   England Head Coach Stuart Lancaster said: “The players will be fully assessed once they get into camp this evening and it’s too early to give any definitive news on their status.   “Tom's ankle and Owen’s knee has been scanned. Owen will see a specialist this evening and we will be able to provide an update on him and the other injured players tomorrow, along with any other potential additions to the squad.”   England start their RBS 6 Nations campaign against Wales in Cardiff on Friday, 6 February.   Back row Carl Fearns (Bath Rugby) and lock James Gaskell (Wasps) will replace Croft and Day in the England Saxons squad for the game against Ireland Wolfhounds in Cork this Friday, kick off 7.45pm.