The 23-year-old made a very quick recovery from a dislocated shoulder to help the Rhinos secure a 24-6 victory over Castleford Tigers during last weekend's Super League Grand Final.
However, the loose forward has now revealed he needs to undergo an operation to avoid any long-term issues with the shoulder and he admits that is the reason why he has not been included in Wayne Bennett's World Cup squad.
"I did quite a lot of damage dislocating my shoulder," Ward told Sky Sports News. "I've got some good movement but long-term it needs sorting out.
"I would have been in the England side had it not been for the operation I'm going to have on Wednesday morning."
Ward, who was also eligible to represent Wales at the World Cup, is now aiming to return to full fitness as quickly as possible.
"For me it's about resting up this off-season, doing some rehab which I'm all too familiar with. It's one of those things," he added. "Going forward I'm not going to participate in the World Cup with England or Wales, and just look at next year."