Chicago Police Superintendent Eddie Johnson is hospitalized Friday after doctors found a blood clot in his lung.

According to Chicago Police Spokesman Anthony Guglielmi, Johnson was undergoing an annual stress test at Rush University Medical Center on Friday when doctors discovered the small clot.

“The Superintendent is in great spirits and wanted to let everyone know that he appreciates the well-wishes,” Guglielmi said in a statement.

According to the department, Johnson will remain hospitalized overnight for observation, and doctors plan to treat the blood clot with medication.