The Cubs and Reds have agreed in principle to a trade that will send pitcher Travis Wood and two minor-leaguers to the Cubs for left-handed reliever Sean Marshall, according to a source familiar with the situation. Marshall, 29, could be used as a set-up man or as a possible closer, due to the fact Cincinnati's closer Francisco Cordero is a free agent. He is set to make $3 million in 2012, and he will be a free agent after the season.