Krsitc is soft because he's a white import. Apart from that, there's no softness in his game. After the "Garbajosa is soft", we have the "Krsitc is soft". Next stop: "Nocioni is soft! I have no idea who he is and I've never seen him play, but he's certainly soft!"
Also, he's not injury prone. He had a major injury in his career, he tore his ACL once. We have a couple of guys in our roster with a little more experience in that department.
The problem is how healthy he is and if he can get return to his old form. But we're talking about a guy who was averaging 17 ppg, 7 rpg, 2 apg, 1 bpg, 53% FG before the injury, averaged 18.5ppg/7.6rpg in the playoffs during his rookie season and is still young (25 years old). He is a subpar defender, but if we can get him cheap and he's good enough physically, he'd be a great addition.