Alabama DL Quinnen Williams reflects on his journey, which took another step forward on as he announced that he would enter the NFL draft. (0:36)

TUSCALOOSA, Ala. -- Alabama's annual exodus of underclassmen to the NFL began again Friday when four players declared for the draft, including star defensive lineman and potential top-five pick Quinnen Williams.

Offensive lineman Jonah Williams and running back Josh Jacobs also declared for the draft in a Friday news conference. Tight end Irv Smith Jr., who was not present, announced his decision on Twitter.

Alabama coach Nick Saban said that Smith couldn't be there because he was going to the wedding of fellow tight end Hale Hentges.

Quinnen Williams was arguably the most dominant defensive player in the country after playing sparingly last season and redshirting the season before. The 6-foot-4, 295-pound Birmingham, Alabama, native won the Outland Trophy, given to the best interior lineman in college football, and finished the season with 71 tackles, 19.5 tackles for loss, 8 sacks and 12 quarterback hurries. ESPN ranks him as the No. 2 draft-eligible prospect.

"I believe it's time for me to take the next step in my football career and declare for the draft," Williams said.

Jonah Williams, whom ESPN ranks as the No. 12 draft-eligible prospect, started every game in his Alabama career, first at right tackle, where he was a Freshman All-SEC selection, and then at left tackle, where he was a unanimous All-American last season. The 6-5, 301-pound junior from California surrendered just two sacks in 831 offensive snaps during the regular season and SEC championship game.

Jacobs, a 5-10, 216-pound junior from Oklahoma, started only one game this season, but he finished strong and wound up rushing for 640 yards and 11 touchdowns to go along with 20 catches for 247 yards and three TDs.

Smith, ESPN's No. 2-ranked tight end, enjoyed a breakout season after catching just 14 passes as a sophomore. He pulled in 44 passes for 710 yards and seven touchdowns in 2018. He is the son of Irv Smith Sr., a former first-round pick of the New Orleans Saints who spent seven seasons in the NFL.