"As of now, he's still a Penn State recruit," Fork Union (Va.) coach Micky Sullivan told ESPN.
Hackenberg has developed a list of questions for O'Brien and Penn State and plans to take a visit to the school before deciding whether to honor his decision to play for the Nittany Lions.
Penn State was docked scholarships and banned from the postseason, among other penalties, by the NCAA and Big Ten on Monday.
Hackenberg (6-4, 210) is a pro-style quarterback who was also recruited by several top programs, many of which have re-engaged the high school senior this week.
Hackenberg's father said Monday that the family would be "cautious."
Sullivan, who wouldn't disclose the other schools who have contacted Hackenberg this week, did tell ESPN "he's been brought up to understand that his word matters."
Two other top recruits, defensive tackle Greg Webb (Erial, N.J.) and cornerback Ross Douglas (Avon, Ohio) decommitted. Tight end Adam Breneman, a top 25 recruit, said he's "100 percent" committed to O'Brien and Penn State.