NEW YORK – NBC News anchor Brian Williams will be off the air for a few weeks soon for surgery to replace a knee that was damaged in a high school football game decades ago.

Yet in what may be a sign of increased competitiveness in an evening news ratings race that Williams has dominated for several years, NBC News would not say Friday when Williams would go under the knife.

Williams, 54, discussed the knee replacement surgery Thursday in a “Nightly News” segment about the procedure by Dr. Nancy Snyderman.

“If you don’t see me around here for a while, this is the reason why,” he said.

Lester Holt will anchor the nightly news while Williams is away.