The Kiwis have suffered a big setback ahead of October's Rugby League tri-series against Australia and Great Britain.
Bulldogs star Sonny Bill Williams is all but ruled out for the rest of the year, including NRL action, and fellow backrower, Penrith's Tony Puletua is battling to overcome a shoulder injury.
Bulldogs doctor Hugh Hazard says Williams' knee injury has been slow to respond to treatment and league medical officials now fear the 19 year old's career is in danger of ending prematurely.
Bulldogs CEO Malcolm Noad has sent a letter to the NZRL outlining Williams' predicament, as well as other injuries to the club's Kiwi candidates.
It is understood Williams can barely walk with the injured knee, and Hazard says if they do not give the young player time to heal, the knee will become arthritic.
The knee injury, sustained 10 weeks ago, has not responded well to treatment.
Puletua's plan to make a comeback for NRL club Penrith this weekend has been postponed indefinitely as he battles a shoulder injury that has sidelined him for 19 weeks.
