I don't think Lee's wrist is broken; he walked off the field under his own power. Correct me if I'm wrong, but people have broken their wrists before and have not had to be carried off the field.
Since he plays for the Cubs, I'm gonna say its an 80-90% chance it's broken. I really have no idea, but it looked really bad. For another team is a 3 to 4 week injury. For the Cubs it's a 3 to 4 month injury.