Tony Burnett, Woodbury Chief of Police, is in Middle Tennessee Medical Center in Murfreesboro.
According to Woodbury Mayor Harold Patrick, Burnett first became ill late last week, suffering from an infection.
Patrick said that it appeared treatment with antibiotics had cleared the infection from Burnett's body, but that over the weekend he began running a fever as high as 103 degrees.
Burnett was admitted to the Murfreesboro hospital on Sunday, and has been undergoing treatment since then for double pneumonia.
Double pneumonia involves inflammation of both lungs. Pneumonia is inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection.
Patrick said Burnett could be released today, if his temperature has been under control for a 24-hour period.
"He's been a pretty sick fellow the last few days," Patrick said. "We wish him all the best and hope that he is released soon."