NBC Sports Anchor Abruptly Exits Kentucky Derby Broadcast Due to Nut Allergy

4:36 PM PT -- Fareed has clarified Mike's medical issue ... explaining Tirico has a nut allergy and suffered a reaction due to it earlier today. He adds Mike is now doing recovering.

Mike Tirico was forced to step away from NBC's Kentucky Derby broadcast coverage after coming down with a mystery illness.

The veteran sports anchor left viewers of the broadcast shocked and concerned on Saturday afternoon when the anchor appeared to have low energy during the pre-Derby show -- which some fans online pointed out after his removal.

Tirico was on the air earlier in the day and seemed okay while anchoring coverage from Churchill Downs. We should note the weather in Louisville is currently cold and rainy.

NBC sports anchor Ahmed Fareed took over the broadcast in the 3 PM hour and said ... "Mike, as you may have heard, is a little under the weather right now." He didn't elaborate any further on Mike's condition.

People took to social media to express concern about Mike's condition -- with many pointing out the differences in his on-air reporting compared to past broadcasts. One user wrote ..."Why are we pretending like Mike Tirico is OK? Something is very wrong."

Another wrote ... "Mike Tirico sounds like he should be in bed sleeping, not covering the Derby."

We've reached out to NBC Sports for comment on his condition.