England have called up Tom Croft and Christian Day to their Six Nations training squad as injury cover for Geoff Parling and Tom Wood.
Leicester Tigers lock Parling is currently struggling with a knee problem, while Northampton Saints flanker Wood is nursing an ankle concern. Both men are being assessed by medical staff.
"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," coach Stuart Lancaster told the Rugby Football Union's official website.
"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 Six Nations campaign against Wales in Cardiff on February 6.