When he first emerged at Leeds he looked like he was going to be a star (similar in potential to Welsby at Saints). Unfortunately, a couple of bad injuries seemed to knock him off course a little, but he has shown signs this year at rovers of recapturing something of his original promise.
I recall him playing for Leeds in a WCC game down under a while back (think he was still a teenager) and Phil Gould mentioned in the commentary that he was impressed by him and felt he had potential to play NRL. Given Gould's notorious apathy and low opinion of SL that was some compliment!
If he can put his injury problems behind him (Walker that is, not Phil Gould!!) then he should be a good signing, giving us options in the backs at the very least.
Fingers crossed it goes well, both for him and the club.