Worcester have suffered an injury setback after flanker Sam Lewis was ruled out for the rest of the season because of a shoulder problem.
Lewis, who has yet to play in the Premiership in 2015/16, requires surgery on the shoulder as he has nerve damage from a pre-season game.
"We've tried a fairly conservative approach, but the problem hasn't had a sufficient response," Worcester boss Dean Ryan told BBC Sport.
"The medical team are now looking at surgical intervention. It stems from having a shoulder impact injury. He will require surgery to try to stimulate a nerve and that will rule him out for the rest of the year."