NEW YORK (AP) — Bob Costas is stepping down from his role as prime-time host of NBC’s Olympics coverage, where he will be replaced next winter in South Korea by Mike Tirico.

Costas has been the on-air concierge to NBC’s Olympics 11 times, starting in 1992. He warmed up as the late-night host in Seoul in 1988.

Costas, 64, said he’s not retiring from the business, but entering the “Tom Brokaw phase” of his career. Brokaw, the former NBC “Nightly News” anchor, is a commentator at big news events and makes documentaries.

The Olympics role requires the host to set the stage for the night’s telecast, guide viewers on switches to different venues, handle news if it breaks and conduct on-air interviews. It was a job popularized by ABC’s Jim McKay in the 1970s. Costas paid tribute to McKay in making his announcement Thursday on the “Today” show.

“I was lucky because I was surrounded by tremendous colleagues — and we kept getting the rights to it,” Costas said.

Tirico was considered the heir apparent for the role since he was hired by NBC from ESPN last year. Costas said it was his choice to leave and although the decision denies him a victory lap in Pyeongchang in 2018, his most recent Winter Olympics memory may not be that pleasant. In Sochi, Russia, in 2014, Costas was sidelined for six days because of an eye infection.

He said his favorite Olympics memory was in Atlanta in 1996, when Muhammad Ali, despite his Parkinson’s disease, was a surprise torchbearer who lit the flame at the stadium.

“Somehow even in that condition he was just as charismatic and magnetic as he’s always been,” Costas said.

Costas and Tirico, 50, have a tie that goes way back. They both graduated from Syracuse University, where Tirico was the first recipient of a scholarship in Costas’ name. Tirico debuted with NBC as part of its team in Rio last summer.