Ko-su-ke for M-V-P

Over in the comment section of a "Roster Talk" post I did recently, vigilant Goat Reader faustus1500 posed a question about the identity of the Cubs' most valuable position player this season. According to Fangraphs, a site I'm very fond of, that distinction belongs to one Kosuke Fukudome, a guy Kurt recently had a few words about whom to say. faustus wondered aloud (or rather, textually...?) if Kosuke was more or less valuable than the Cubs current 1B, Mr. Derrek Lee.  To address faustus' question, I will consider a concept that is extremely valuable in determining a player's value to his team--replacement. Imagine, if you will, a 2009 Cubs season in which Derrek Lee ended up missing a ton of time.* Who would play at first?  (*Note - I realize Aramis Ramirez actually DID miss a bunch of games, and is himself the most reasonable choice for Cub MVP. However, this discussion focuses on Cubs who actually were healthy this season. ...