England boss Eddie Jones has suffered another injury worry ahead of the Six Nations with flanker Brad Shields missing Wasps' Heineken Champions Cup clash against Leinster.

Wasps announced 90 minutes before kick-off at the Ricoh Arena that Shields would miss Sunday's Pool One encounter due to a side strain.

Saracens, meanwhile, said on Saturday that their fly-half and England captain Owen Farrell had undergone thumb surgery.

New Zealand-born Shields, who has won five caps, started England's autumn Tests this season against South Africa, New Zealand and Australia.

He was named on Thursday in head coach Jones' 35-man squad to prepare for England's Six Nations opener against Ireland in Dublin on February 2.

"Wasps have been forced into a late team change ahead of their Heineken Champions Cup clash with Leinster Rugby, as Ben Morris steps in for Brad Shields who misses out with a side strain," Wasps said.

Press Association Sport understands that Shields' absence from the Leinster game could be more precautionary rather than anything long term.

Jones, meanwhile, must decide whether to call up injury cover for Farrell.

Farrell has undergone a procedure to repair ligament damage and is expected to return to action in seven to 10 days, a time frame that would enable him to play against Ireland.

However, with England departing for their pre-tournament training camp in Portugal on Wednesday, his ability to take part in training could be severely restricted, throwing Jones' preparations into turmoil.