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Prop Joe Marler has been added to England's growing injury list ahead of the Six Nations.
It comes amid front-row concerns for England head coach Steve Borthwick ahead of the Six Nations.
Marler's fellow loosehead props Ellis Genge, Bevan Rodd, Mako Vunipola and Val Rapava-Ruskin are also on the sidelines.
Borthwick's problems include a four-match ban being imposed on Saracens' Vunipola, who was sent off for a dangerous tackle against Premiership opponents Newcastle.
Although he will be available if required for the Six Nations, experienced campaigner Vunipola cannot play again until after Saracens™ Premiership appointment with Exeter, which is only a week before England™s Six Nations opener against Italy on February 3.
Genge, an England captaincy contender following Owen Farrell's decision to miss the Six Nations, last featured for his club Bristol on December 2. He has been sidelined due to a hamstring injury.
Sale forward Rodd is out for the rest of this season after undergoing toe surgery and Gloucester's Rapava-Ruskin, who was part of England's World Cup training squad last year, is another long-term absentee following a knee operation.
On the 88-cap Marler, who was hurt during Quins' victory over Gloucester 10 days ago, the club's head coach Danny Wilson said: "There is still a little bit of assessment going on.
"Joe is a week-by-week process at the moment to make a full assessment of the time period and the time frame.
"He is not going to play this weekend - that is pretty clear - but what I can't give is a time frame. There have been a few twists and turns with it. We are kind of in the middle of a full assessment.
"I know that is going to sound a little bit like it is taking a while to assess, but there is a little bit to this one so I am probably not really going to be able to give you much.
"Until we get a full picture and a full time frame, and we are in that process at the moment, then I can™t really tell you a huge amount."
