Supreme Court Justice Anthony Kennedy will retire this year, according to a Republican senator.

Politico reports Sen. Dean Heller (R-Nev.) said in a speech last week that he expects the 81-year-old justice to step down this summer.

"Kennedy is going to retire around sometime early summer," Heller said. "Which I'm hoping will get our base a little motivated because right now they're not very motivated. But I think a new Supreme Court justice will get them motivated."

According to The Hill, Kennedy, who was appointed by President Ronald Reagan in 1988, is considered the most pivotal justice on the U.S. Supreme Court and is often casts the tie-breaking vote in contentious decisions.

Kennedy, considered a conservative judge, has been rumored to be contemplating retirement for months. The New York Times reports most justices typically step down under presidents from the same political party as whomever appointed them, as "deciding when to step down from the court is not a judicial act."

Reagan was a Republican and President Donald Trump was the GOP nominee in the 2016 election. Trump currently has a Republican-majority Senate and House, but if Kennedy retires a battle is expected over who will replace his seat.

Trump successfully nominated Neil Gorsuch last year to replace Justice Antonin Scalia, who died in 2016, while President Barack Obama was still in office.

According to Politico, Heller said "Mike Lee from Utah is probably on that short list of the next Supreme Court justice in our courts."

Other potential replacements have not been named, but The Hill points out Kennedy may not be retiring so soon. He hired four law clerks in January for the October term.