Castleford have confirmed that half-back Luke Gale is set for a long spell on the treatment table.
The England international, who was recovering from close-season knee surgery, has suffered another injury in training, and will be assessed further by a specialist this week.
Gale struggled with injuries last season, being limited to just 15 appearances, and his most recent injury is likely to rule him out of the entire 2019 campaign.
On Gale’s injury, Tigers’ director of rugby Jon Wells said: “Luke has suffered a suspected ruptured Achilles tendon during training over the weekend.
“He will be seeing a specialist to assess the seriousness of the injury but unfortunately, the prognosis doesn’t look great.
“The whole club is gutted for Luke, who had been progressing really well following off-season surgery to his knee.
“This is likely to be another significant setback for him but having known Luke for many years, I know that he is an extremely strong character and a resilient member of our squad who will be doing everything he can to overcome this latest hurdle and return fit and healthy to the Tigers’ fold in the future.”