The decision comes after Hines initially opted out in September, saying at the time that he'd recently lost someone close to him due to COVID-19 but that he was not planning on entering the draft, citing his two remaining years of eligibility.
In a social media post on Monday, Hines thanked the coaching staff for being supportive of him throughout the opt-out process.
Hines was Texas A&M's second-leading tackler (73) last season. He ranked second on the team in tackles for loss (10.5) and fourth in quarterback hurries (4).
Texas A&M, despite losing Hines and leading receiver Jhamon Ausbon to opt-outs, has played well this season, ranking No. 5 in the polls with a record of 5-1.
The Aggies defense ranks fifth in the SEC in points per game (25).