Georgia Republican Sen. Johnny Isakson announced Wednesday that he will resign from the Senate, citing health reasons.

“After much prayer & consultation with my family and my doctors, I have made the very tough decision to leave the U.S. Senate at the end of this year..my health challenges are taking their toll on me, my family and my staff. My Parkinson’s has been progressing,” Isakson said in a statement.

“With the mounting health challenges I am facing, I have concluded that I will not be able to do the job over the long term in the manner the citizens of Georgia deserve. It goes against every fiber of my being to leave in the middle of my Senate term,” he continued.

There will still be three years left on Isakson’s term when he departs office. (RELATED: Sen. Johnny Isakson Hospitalized After Serious Fall)

Georgia Republican Gov. Brian Kemp will now get to appoint a U.S. senator. Whoever he chooses will have to run in 2020, and then they will have to run again in 2022.