Murphy has been terrible, but I understand that particular gamble. When healthy, Murphy provides elite-level rebounding and shooting (along with very poor defense). He could have been a valuable player, and I understand why Danny was intrigued.
Unfortunately, he's just not right this year. When a shooter injures his back and legs, that can kill his game, and that seems to be what has happened to Murphy. There were some rumors out of NJ that he was cooked, and I guess they were true.