England have been dealt a fresh injury blow ahead of their 2017 Six Nations opener against France this weekend. The defending Grand Slam champions confirmed on Tuesday night (31 January) that George Kruis is set to undergo further medical assessments today to determine the full extent of a knee problem suffered during a training session at their Pennyhill Park base in Surrey.

While Kruis' availability has yet to be determined, the Saracens lock will no doubt be desperate to feature against Les Bleus having only recently proved his fitness following a fractured cheekbone sustained against Newcastle Falcons on Christmas Eve.

His absence could threaten to disrupt head coach Eddie Jones' best-laid plans to switch club teammate Maro Itoje to the back row. The versatile 22-year-old, who missed England's autumn victories over South Africa, Fiji, Argentina and Australia due to a broken hand, is expected to start at blindside flanker with former captain Chris Robshaw ruled out of the entire tournament after undergoing shoulder surgery.

In the event that Kruis is ruled out and Jones still decides to field Itoje at six, then Joe Launchbury and the big-tackling Courtney Lawes would likely resume their partnership in the second row. Northampton's Tom Wood looks set to continue at openside and Wasps' Fijian-born powerhouse Nathan Hughes should deputise once again for first-choice number eight Billy Vunipola, who, like older brother Mako, is still recovering from his own knee issue.

George Kruis
George Kruis is now doubtful for France's visit to Twickenham David Rogers/Getty Images

In addition to confirming Kruis' injury, the Rugby Football Union (RFU) also revealed which 25 players have been retained by England in the build-up to Saturday's (4 February) clash at Twickenham. Joe Marler is included alongside fellow loosehead props Matt Mullan and Ellis Genge after recuperating from a fractured leg in just three weeks, while flanker James Haskell also makes the cut after missing the initial stages of last week's Vilamoura training camp with foot soreness.

Jonny May remains present despite reportedly receiving stitches to an eye cut sustained during an accidental clash of heads. He is believed to have had his head bandaged but apparently did not require a head injury assessment. Fellow wing Jack Nowell missed training on Tuesday but is thought to be fine to play. Jones is due to name his matchday 23 tomorrow.