Thompson had three sacks and was named MVP in Georgia's Liberty Bowl win over Texas Christian following the 2016 season. He had no sacks in 2017.
Thompson, from Albany, Georgia, helped lead this year's team to its first Southeastern Conference championship since 2015 and a spot in the national championship game.
He had 38 tackles, including 3 ½ for loss, this season.
Thompson announced he was entering the NFL draft on his Instagram account. He wrote the decision followed "long discussion with my family and coaches."
He added "playing in the NFL has been a lifelong dream of mind and I'm excited to see what the future holds."
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