All three announced their decisions Wednesday on social media. Tailback Kerryon Johnson has also declared his plans to turn pro.
Davis is a second-team Associated Press All-American who started all three seasons at Auburn, including as a true freshman.
He is projected as an early round pick with some mock drafts having him go in the first round.
Davis had 36 tackles, 11 pass breakups and an interception this season. Holland was one of the Southeastern Conference’s top pass rushers with 10 sacks.
Pettway played in only five games this season due to injuries and suspension. He ran for 305 yards and five touchdowns after leading the Southeastern Conference in yards per game in 2016.