(AP) -- Bob Costas is getting a new substitute on NBC's Olympics broadcast on Friday. It's Meredith Vieira.
Costas will be sidelined for a fourth day as NBC's prime-time host because of an eye infection, andMatt Lauer filled in for him three days in a row. But with Lauer also anchoring the Today show - and making himself available for stunts like a luge ride on Friday's show - Olympics producer Jim Bell says he needs a break.
Bell said Friday that Costas is improving, but for someone with an infection that makes him sensitive to light, a television studio is a lousy place to be.
Vieira, who was Lauer's former co-host on Today ,co-hosted the opening ceremony with him last week.
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