Clay Buchholz was pulled from his scheduled start earlier in the week, and it was announced earlier today that he had entered the hospital. We have now learned that that the internal bleeding is likely caused by anti-inflammatory medication such as ibuprofen and Buchholz will likely need 10-14 days to recover (via Joe Amorosino of WHDH).
The condition can be serious, even life threatening, if not treated properly. This kind of thing can leave a player at less than full strength for an extended period of time. Red Sox fans hope that Buchholz caught things early enough that quick treatment will see him make a full and speedy recovery.