The Championships are due to take place on August 30th at King's Lynn.
Crump was due for surgery on his broken kneecap earlier this week and has admitted that he will not return to the track until he his fully fit, which may mean missing out on the next round of the Grand Prix series in Sweden on August 11th.
Defying the injury, the reigning world champion raced in the Czech Republic Grand Prix but believes that he should finally take the time out to recover, explaining how he owed it to his fans.
He said: "I wanted to try and prove myself that my World Championship dream was not over for 2007, but right now I guess it is.
"I am suffering big-time with the knee, and the operation on Monday cannot come quick enough just now.
"It is the one time in my speedway career that perhaps I have put myself before my club, and I want to apologise right now to all the Poole fans.
"I am determined to come back and help the Pirates in their final push to the championship - and let me say that if I do not feel ready for Malilla, which was my goal before tonight, then I will not rush back to do it.
"(Promoter) Matt Ford has told me he wants a fit Jason back and I owe it to Poole to do just that."
