Hull FC captain Gareth Ellis has been ruled out for up to six months after undergoing Achilles surgery.
The 34-year-old suffered the injury in the first half of Friday's 22-12 derby win at Hull KR.
The former England and Great Britain international tweeted on Monday: "Road to recovery starts today, thanks again to everyone for your kind messages of support, really appreciate it."
He made 13 Super League appearances this season, scoring one try.
Meanwhile, the Black and Whites will find out on Wednesday whether half-back Leon Pryce will need shoulder surgery that would end his campaign.
The 33-year-old suffered the injury against the Robins and could be out for six weeks if an operation is not required.