Bob Costas is being temporarily replaced by Matt Lauer on Tuesday, Feb. 11 during NBC's 2014 Sochi Winter Olympics primetime coverage after the sportscaster's eye infection spread from his left eye to both eyes. Credit: NBC; Peter Kramer/NBC/NBC NewsWire

It's time to sit on the sidelines, Bob. NBC sportscaster Bob Costas' eye infection worsened last weekend, spreading from his left eye to both eyes, as seen Monday night during the network's 2014 Sochi Winter Olympics primetime coverage. Costas announced on the Today show Feb. 11 that he will be sitting out for Tuesday evening's primetime telecast, with colleague Matt Lauer taking his place.

Costas, who spoke to his replacement over the phone Tuesday, explained how the condition had worsened using baseball terminology: "Reluctantly, I was trying to throw a complete game here, but I think we’re going to have to go to the bullpen. I don’t know if you’re aware of this or not, but you’re Mariano Rivera, at least tonight," he told Lauer.

Lauer replied, "So, I'm going to step in for you tonight, the master of Olympic primetime?"

"I believe that's it," responded Costas. "Let's hope it's only tonight because right now I am walking around and might as well be playing Marco Polo. I have no idea where I am."

This will be the first time since 1988 that Costas will be sidelined from hosting NBC Olympics primetime coverage. "I just feel bad for him," his replacement Lauer told "He looks forward to these Games for so long, and he's the best that's ever done it. If he could be in that seat, he'd be in that seat."

Costas -- whose one eye has appeared red, puffy and all around painful-looking since the Sochi Winter Olympics started last week -- has been wearing a pair of rounded hipster frames on-air after contracting the infection. "I have no choice to go all Peabody and Sherman on you for the next couple of nights since I woke up this morning with my left eye swollen shut and just about as red as the old Soviet flag," Costas shared Thursday night.

"According to the NBC doctors here, it's some kind of minor infection which should resolve itself by the weekend," he continued. "If only all my issues would resolve themselves that quickly, but that's another story."

For more on the 2014 Winter Olympics in Sochi -- including personal stories from the Team USA athletes, and tons of photos -- pick up Us Weekly's special Olympics bookazine!