He just wasn't loud on the video of him delivering a crushing pancake block against the Jacksonville Jaguars on Sunday that went viral Monday.
The Colts, according to a team spokesman, took the audio of Nelson screaming from another play and added to the play where the No. 6 pick in this year's draft pulled and flattened Jaguars safety Barry Church into the ground on a Marlon Mack run to the right side in the first half.
Video of the play from the Colts' Twitter account was one of the most talked about events on social media Monday. It was up to more than 11,000 retweets and 37,000 likes on Twitter on Tuesday afternoon.
"I saw it got pretty viral on the internet, which was cool," Nelson said Tuesday. "...Yeah, I wasn't yelling, not on that play. I don't know how it got amped up like that."
The play where Nelson's scream occurred was during a play when quarterback Andrew Luck ran a bootleg to the left for 7 yards late in the first half. Nelson pulled to the right and he said he screamed to be a decoy on the play.