On replacing James Russell, there has to be someone that can give the Cubs better than a 10+ ERA with a 2 WHIP and about four innings a start.
With Ryan Dempster stinking up the joint nearly as bad as Russell, you have to leave Jeff Samardzija in middle relief, because he's been the only guy down there that's been able to get anyone out.
Kevin Millwood is available. He could probably be a slight improvement over Russell.