Arizona Sen. Jon Kyl is expected to retire from the Senate at the end of the month.

The Republican senator returned to the chamber in September after Gov. Doug Ducey appointed him to replace the late Sen. John McCain. He previously served three terms in the Senate from 1995 to 2013. 

“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. Over the last few months, Senator Kyl served with the same integrity and statesmanship that marked his 26 years in Congress,” Ducey said in a statement.

“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,” the statement continued. 

Ducey, a Republican, also said a replacement “will be announced in the near future.”

If Kyl’s replacement can be named and sworn in ahead of noon on Jan. 3, he or she will become Arizona’s senior senator in the next Congress, jumping the line of the incoming freshmen — including Democrat Kyrsten Sinema, who was elected last month to the other Arizona Senate seat vacated by Republican Jeff Flake.

Whoever is chosen to replace Kyl will have to stand for election in November 2020 for the final two years of McCain’s term. 

Ducey’s decision will take into consideration the GOP’s viability holding the seat in two years. The appointee would likely be expected to run in 2020 and could potentially face a crowded Republican primary.

A GOP strategist in Arizona named Ducey’s former chief of staff Kirk Adams as a potential appointee. Adams wrapped up his service in Ducey’s office Friday, which makes him available to ascend to Washington if appointed. Other names thought to be under consideration include Maricopa County Attorney Bill Montgomery and state Treasurer Eileen Klein.

Montgomery might be able to ward off other GOP primary challengers, the strategist said. His record as a county attorney, conservative credentials and military experience could keep challengers at bay.

“I just don’t think there’s any appetite for Martha [McSally],” the GOP strategist said of the 2nd District congresswoman and recently defeated GOP Senate nominee.

Donors are also moving away from McSally as a potential appointee after she came up short against Sinema last month, shaking donor confidence. Sinema was the first Democrat to win a Senate election in Arizona in 30 years. 

“There is momentum building for an ‘Anybody But McSally’ appointment among the Arizona donor community,” said Dan Eberhart, a prominent GOP donor in the state.

At least one consultant in the state disagrees.

“The two best cases that can be made can be made about Kirk Adams and Martha McSally,” said Barrett Marson, a GOP consultant in Arizona who worked for a Super PAC backing McSally in 2018.

Marson said McSally would still be a strong contender despite losing to Sinema, citing her fundraising ability and compelling personal story as the first female fighter pilot to fly in combat.

Watch: Jon Kyl Sworn In to Senate, Again

Katherine Tully-McManus contributed to this report.