"I didn't even know I had it," Davis said of his infection. "It was out of the blue."
After doctors noticed something out of the ordinary following Davis' physical last week, the first baseman flew back to New York for additional testing. That revealed the lung infection, which is not even serious enough for doctors to prescribe Davis antibiotics.
Davis said he has experienced no symptoms of the infection but will likely undergo a follow-up examination later this spring.
"I don't feel sick," Davis said. "Honestly, I feel fine."
Davis, who missed the final four months of last season with a bone bruise in his left ankle, was batting .302 with seven homers in 36 games prior to his injury.