Anderson injury ko
A stress fracture to a bone in his left foot was immediately diagnosed when he reported discomfort at the start of training.
The club feel the injury could have been picked up some three months ago, and he will have to wear a protective cast for at least a fortnight.
Hull chief Peter Taylor said: "It is disappointing for everyone but I suppose it could have been a lot worse.
"We're hopeful that John will be back playing again fairly quickly and I do feel sorry for him because he's worked very hard in pre-season.
"The X-rays suggest it is an old injury that has flared up on the hard grounds and John's been very unlucky."