My feeling on injury risk players like Higgins is that they are worth the punt if you are really sure on what the upside is. ie, Chapman, Cox (this year), Drummond (prev years). As long as they are fit you know you are going to get the big scores out of them. With Higgins however I don't see the regular big scores to justify the risk.
Another player like that this year is Jack Grimes. However in his case I see some really big regular scores while he stays fit.