Buchholz was taken out of the Red Sox starting rotation last weekend after falling ill with what was initially diagnosed as a gastrointestinal disorder.
After being placed on the DL Sunday, he was evaluated at Massachusetts General Hospital where it was determined the hurler had esophagitis, characterized as "an erosion of the esophagus and an associated gastrointestinal bleed."
Buchholz is expected to make a full recovery, the Red Sox said.
The 27-year-old right-hander has had an up-and-down season with the Bosox, starting poorly but then improving, going 5-1 with a 3.35 ERA in his last eight starts.
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