Cubs Targeting Lieber?

According to Bruce Levine, the Cubs could be looking to sign Jon Lieber. Lieber, a former 20 game winner for the Cubs, could be a capable 5th starter for the Cubs. I wouldn't really like this signing. Why not go after a guy like Bartolo Colon if you were interested in signing a guy coming off an injury? Colon would present more upside than Lieber would. I would rather have Gallagher to be the 5th starter than either of them anyway.