PHOENIX (3TV/CBS 5) -- Senator Jon Kyl turned in a resignation letter stating he will leave the U.S. Senate on Dec. 31.
Kyl gave the letter to Gov. Doug Ducey Thursday afternoon.
[READ MORE: Kyl sworn in to U.S. Senate]
Ducey appointed Kyl to fill the late Sen. John McCain's seat in September after McCain's funeral.
Upon accepting the position, Kyl said he would only commit to filling the seat until Jan. 3. Kyl previously served alongside McCain in the U.S. Senate from 1995 to 2013.
"Senator Kyl didn’t need to return to the Senate. His legacy as one of Arizona’s most influential and important political figures was already without question. But he did return, and I remain deeply grateful for his willingness to step up and serve again when Arizona needed him. I wish him and his family all the best," Ducey said.
His resignation leaves the seat open for Ducey to appoint someone yet again.
Ducey said he will appoint someone soon, but there is no word on who is in the running.
McCain's term ends in 2022.
When Jon Kyl returned to the Senate in September, our country faced many critical issues. Arizona needed someone who could hit the ground running from day one and represent our state with experience and confidence – and that’s exactly what Senator Kyl has done. (1/3) https://t.co/z7xaOO0p3L— Doug Ducey (@dougducey) December 14, 2018