If Ruben Wolkowyski is to get off the IR and contribute for the Mavs, writes Gerry Fraley, he'll have to knock some people down.  Though not soft, Wolkowyski isn't particularly brutish, which is what coach Nelson wants.  "For the body that he has, that's one thing he needs to focus on," assistant coach Donnie Nelson said. "He needs to get in there and be willing to knock guys down, be an enforcer of sorts."