(CNN) Colin Kaepernick first knelt during the national anthem on September 1st, 2016.

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In the nearly 13 months since the former NFL quarterback took a stand by taking a knee, tight end Julius Thomas had never followed suit -- until Sunday. So, what changed?

"After I heard the President's comments -- and just the difference in characterization he had for my fellow peers taking a silent protest, in comparison to the way he characterized people that were preaching hate -- it really struck me," Thomas told Erin Burnett Monday evening.

During a Friday night speech in Alabama, President Donald Trump labeled NFL players as "sons of bitches" for failing to stand during the National Anthem.

"When I watched it, I was just truly hurt," Thomas, now a Miami Dolphin, said. "I don't think a lot of people truly understand what it feels like to wake up in this country and not feel equal."

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