Parsons becomes the third high-profile prospect to opt out of the college football season in the past week, following in the footsteps of Virginia Tech cornerback Caleb Farley and Minnesota wide receiver Rashod Bateman.
ESPN's Todd McShay ranks Parsons as the sixth-best prospect in his top-32 player rankings.
In a video he posted on Instagram, Parsons said he felt comfortable with the health and safety standards at Penn State but the potential risk to his young son "far outweighed my urge to play football this season."
"Therefore," he said, "I have decided to opt out of the 2020 season and prepare for the 2021 NFL draft. I will be graduating early and getting my degree in December."
Parsons became an ESPN and Associated Press All-American in his first full year as a starter last season. He totaled 109 tackles and four forced fumbles, including an exceptional bowl game where he finished with 14 tackles, two sacks, three tackles for loss, two forced fumbles, two pass breakups and a quarterback hurry.