England's preparations for their Six Nations opener against Ireland have been thrown into disarray by a thumb injury to captain Owen Farrell.
Farrell is undergoing a procedure to repair ligament damage and is expected to return in seven to 10 days, making him available for the title showdown in Dublin in a fortnight.
However, with England departing for their pre-tournament training camp in Portugal on Wednesday the Saracens playmaker's ability to train will be severely restricted.
The worst case scenario would mean he is unable to take part in sessions until four days before the Aviva Stadium showdown.
"It's a simple procedure and he should be back in seven to 10 days," Saracens director of rugby Mark McCall told BT Sport before the Champions cup clash with Glasgow.
In the event Farrell suffers a setback, his place at fly-half would be taken by George Ford with Henry Slade providing further cover after Danny Cipriani was omitted from the training squad named by Eddie Jones on Thursday.
Ford could also take Farrell's leadership duties as Dylan Hartley is recovering from a knee injury.
