Joy, 22, was the Roughyeds player of the year last term, but has been struggling for several weeks, and is still on a programme of intense rehabilitation.
He has no chance of playing against Scorpions in Maesteg on Sunday (March 2) and he is unlikely to be ready for the first home game against Hemel Stags on March 9.
Coach Scott Naylor said: “I’m told he might be available for selection by the middle of March, but by then he won’t have done a field session with the squad for seven weeks.
“Before we can think of throwing him in for his first game since last September he’ll need to be cleared to start training with the squad again and perhaps have a run-out with the under-20s.
“It will be nice to have him available for selection again, but in the meantime the other props will be pushing to keep their spots and we’ll have to look at how they are performing.
“In Phil’s case it’s hard to be specific about when he’ll be ready.”