Should this be Derrek Lee's last year with the Cubs?

Today's most interesting Cub-related news comes from a report filed by Bruce Levine, which says that Derrek Lee isn't interested in negotiating a contract extension during the season. That line of discussion raises a question: should the Cubs be interested in negotiating a contract extension for Lee at all? Sure, there are enough reasons to support investigating what it would take to bring Derrek back. He's a fantastic hitter, an annual Gold Glove candidate, and perhaps most importantly, the closest thing this team has had over the past decade to a bona fide clubhouse leader. Lee is soft-spoken, mature, and as far as I can tell an all-around upstanding guy. He was also an absolute beast in 2009. He truly carried the team, with a .306/.393/.579 slash line that somehow understates his contributions over the course of an extremely tough season (I mean, when Aramis was injured, did he ever have any sort of protection in the lineup?). However... Like it or not, there ar...