Meredith Vieira will host NBC’sMeredithVieira110913221045-275x275 primetime coverage of the Sochi Olympics again tonight. Last night she made history, becoming the first woman to ever anchor NBC’s primetime Olympics coverage. She’s filling in for Bob Costas, whose nbcsochi__131202172913__140212145821eye condition is “improving” but is still “day to day,” NBC Sports told Deadline. Vieira, who’d been brought to Sochi to co-host the Opening Ceremony with Matt Lauer and has since been doing segments for Today on U.S. athletes to watch at the Games, was tapped yesterday to replace Costas as the network’s primetime Games anchor. She took over for Lauer, who’d pulled double duty for three days. Costas still is battling an infection in both eyes that makes studio lighting his enemy, though he too may have made TV history: first anchor on record with Twitter trending eyes.

NBC’s Games EP Jim Bell said in a phoner with the press Friday that Vieira was likely on duty for two nights as Costas continues to recover from pink eye. Bell called her the best choice for the gig among a considerable stable of talent at Sochi because her schedule was most flexible. For a TV veteran whose new syndicated daytime talk show is set to launch in the fall, the Sochi exposure is a gift. Before Costas, former Today anchor Bryant Gumbel served as primetime host of NBC’s Olympic coverage and was preceded by Curt Gowdy and Bill Henry, making Vieira the first woman to do the job. (Hannah Storm, Mary Carillo, Gayle Gardner and Jane Pauley have previously hosted NBC’s daytime and late-night Olympic coverage.)

Now the question becomes whether Costas will be back for Sunday’s Games coverage. In a radio interview with Ryan Seacrest on Thursday Costas had said he hoped to be back at work by the weekend. In various interviews, Costas has said he feels okay but can’t come back to work because of the specific nature of his eye infection — in some reports suggesting studio lighting, and makeup, may have exacerbated his condition.

“It’s so funny, I woke up this morning and I was feeling fine, and now my eyes are killing me,” Vieira joshed on Today Friday morning when she was revealed as Costas’ next understudy. “I watched you guys [Lauer and Al Roker] attempt the luge — I think I’m going blind.”

Bell has brushed off press suggestions the network might be ready to  “shut down” Costas as its primetime anchor. “Getting into next week, it may become a topic of conversation, but we’re not there,” Bell said. Costas continues to deal with the effects of an infection that began in his left eye and spread to his right eye earlier this week. That was TV-historic too, ending Costas’ streak of 157 consecutive appearances as NBC’s Olympics anchor in primetime. It was the first time since 1988 Costas did not host the coverage. He’d soldiered on with the infection in one eye — then two — the first few days of NBC’s Olympics coverage before calling Lauer in from the “bullpen” on Tuesday.” Lauer told viewers that night Costas looked like the loser in a prize fight. Lauer for three days co-anchored Today show before stepping in for Costas in primetime and late night.