I don't see Kenyon Martin here, and I haven't heard that he's eager to or on the verge of signing here. Also, why keep Hill over those LO and Martin? Because he's still young (only 25, only been in the league 4 years) and not close to retirement and has shown potential and plays with tons of heart and hustle which is not easy to find. One of the reasons we're in the position we're in right now (old, broken down, having to start over next season) is because we didn't keep and develop enough young and athletic players, Hill is still both. We rent Martin dor a season at the expense of losing Hill, where does that leave us when Martin is gone? starting over again, looking for another old PF willing to sign here for a season.
The only reason I ever consider trading him is one you pointed out, injury. If he continues to get injured and proves to be injury prone, then I trade him if I can or just let him walk. As he is healthy though, you aren't getting equal value for him in a trade, or getting a player as good as him at his position for the money he makes. Blake, on the other hand, I would trade him no problem, I've overall been disappointed with his Laker career and he gets injured too much for sure, freak accidents or not.