"2020 has been an unprecedented year, filled with uncertainty due to a pandemic that has forced all of us to adapt as best as possible," Hill said in a statement posted to Instagram. "With that, and after much prayer and discussion with my family, I have decided to opt out for the remainder of the season and declare for the 2021 NFL Draft. This has been an incredibly difficult decision, but one that I feel is best for me at this time.
"These last 3 1/2 years have been some of the best years of my life and I will never forget my time here in Starkville. Mississippi will always be my home. We've made history together, both on and off the field, and as we move on to the next level, that work will only continue."
Hill came back for his senior season after initially declaring for the previous draft. Last month, it was reported that he was expected to opt out.
He missed Mississippi State's last game on Oct. 17 for undisclosed reasons.
Hill had run for 58 yards on 15 carries in three games this season. He caught 23 passes for 237 yards.
The Columbus, Mississippi, native made headlines nationally this offseason when he threatened to boycott the season if the state did not change its flag, which featured the symbol of the Confederacy.
The state ultimately voted to take down the old flag and design a new one.