According to Gordon Wittenmyer’s twitter, Carlos Zambrano has been sent to the hospital with an appendicitis (or at least appendicitis-like symptoms). If he ends up having it out, he could be out for several weeks. We’ll update as we get more information.
UPDATE: From cubs.com, the Cubs have determined it probably isn’t an appendicitis. Zambrano was complaining of lower abdominal pain, so the Cubs were taking every precaution. No update yet on what the actual problem is, or how long Z will be out.