The Wales back suffered a ruptured left achilles tendon in the region’s Heineken Cup game against Exeter last Saturday.
After undergoing surgery this morning to repair the injury, the 25-year-old will be out for an anticipated period of six months.
Easterby, who suffered a similar injury as a player said: “It’s a big blow for Rhys and for our region to lose a player of his quality.
“He was coming through well in the last couple of games of the autumn, put in a strong performance against Australia and was making a real impact in our game against Exeter – so it’s very difficult for him to take.
“I am sure that a player of his experience, intelligence and ability will deal with this very well and after a couple of weeks away to recover from the surgery, will be back and remain a very positive influence in our environment.
“He’s a player with a very good rugby brain and there will be a lot he can do to work in and around our environment to help the team, some of our younger players and in our preparations for the rest of the season.
“We all want to show him as much support as we can right now, it’s going to be a tough couple of weeks for him but the boys here are a very close-knit group so I’m sure that will be a positive for him.”
Priestland’s injury means he joins a number of other Welsh internationals on the sidelines and means he is unlikely to take part in this year’s Six Nations.
Scarlets Head of Medical Andy Walker said: “The surgery was undertaken this morning at the Vale Hospital and has gone very well. It’s a difficult injury but we have been fortunate to have had the injury assessed and repaired surgically so promptly and by a very experienced ankle and foot specialist.
“The anticipated time off the field is around six months but it all depends on the individual and how his rehab goes in the interim.
“He’ll be non-weight bearing for two weeks now, in plaster and then into a cast boot and then we’ll start rehab at a later stage. This is a serious injury and the most important thing is that the medics do everything possible to ensure a strong recovery and not to rush the process at any stage.
“We’ll be working closely with him to ensure we keep him the best medical support possible including all the right nutrition to aid recovery so that he’s hydrating and eating well.”
