Sen. Tim Johnson is expected to remain in the hospital for several days as he recovers from an operation to remove his gallbladder, his office said Wednesday.

The South Dakota Democrat had his gallbladder removed Tuesday after being admitted to the Avera McKennan Hospital & University Health Center on Monday with a high fever.

“Sen. Johnson had an acute gallbladder infection and will remain in the hospital a few days on an IV antibiotic. He is doing well,” his doctor, Scott Beckstrand, said.

“The Senator is feeling much better. I expect him to make a full recovery,” Johnson’s surgeon, Dr. Donald J. Wingert, added.

Johnson’s office released a statement from the Senator saying: “I’m feeling good and they already have me up and moving around the room. I’m following doctors’ orders and trying to rest, but I look forward to getting home.”