On Thursday, athletic director Dave Joyner is expected to announce at a Beaver Stadium news conference that a search committee is actively looking at candidates to interview. The list probably will include people with Penn State ties such as Miami coach Al Golden and former Rutgers coach Greg Schiano, as well as Vanderbilt coach James Franklin.
However, given the uncertainty as to what the recruits may do, the search for a new head coach must be more expeditious than it was two years ago when O'Brien was hired after an exhaustive hunt that took 40 days to complete following the Nov. 9, 2011 firing of Paterno.
One Penn State recruit, defensive tackle Antoine White of Millville High, told The Inquirer: "I'm not making any statements at this time. But I am keeping my options open right now."
White is expected to be one of the recruits who will enroll for the spring semester, which begins Jan. 13. Quarterback Michael O'Connor, wide receiver DeAndre Thompkins, offensive tackle Chasz Wright and defensive tackle Tarow Barney also are expected to start then.
Those not enrolling in the spring can sign their national letters of intent on Feb. 5.
Penn State's first commitment for 2014, running back Mark Allen of Hyattsville, Md., issued a series of posts on Twitter shortly after news of O'Brien's acceptance of the Texans' offer surfaced.
"It's my job as a leader of this 2014 recruiting class to keep our class together," Allen said. "Coach O'Brien did what he had to do but PENNSTATE, I just want y'all to know I'm going to stick to my word and I will be in my dorm June 28th.
"I'm going to stick by pennstate side. Regardless the new head coach I will be attending Penn State."
Over the weekend, O'Brien told some recruits, particularly four-star Brooklyn, N.Y., defensive tackle Thomas Holley, that he was staying after reports of his negotiations with the Texans became public.
Giving Johnson the authority to try to keep the recruiting class together is vital because coaches from other schools, who may have told the recruits that O'Brien would be leaving for the NFL sooner rather than later, will be back on the phones trying to get the players to change their commitments.
And it's not just the high school seniors and transfers who need to be persuaded to stay. Wide receiver Allen Robinson, who was named Big Ten receiver of the year in each of the two seasons playing for O'Brien and receivers coach Stan Hixon, is likely to leave now that O'Brien is expected to take Hixon with him to Houston.
The father of quarterback Christian Hackenberg, who was O'Brien's first commitment after he was hired, said he wants to see what happens in the next week or two, and left the door open just a little about his son's leaving.
"Until we have all the information, we have to wait," Erick Hackenberg told the Harrisburg Patriot-News. "I'm not saying he will or won't [return] - and that sounds bad, but it's neutral."
A new head coach ideally would have to be in place as soon as possible, at least by the end of next week. It won't be as uncertain a situation as two years ago, when no one could predict what, if anything, the NCAA would do in the wake of the Jerry Sandusky child sex abuse scandal.
The NCAA levied sanctions in July 2012, but some scholarship restrictions were relaxed last September. The program still faces a postseason ban through 2015.
However, there remains instability in the university's administration. President Rodney Erickson is expected to leave his post no later than June 30, if not sooner. A new president probably would hire his or her own athletic director, meaning Joyner likely would be out of a job.
Plus, the cases of three of the key figures in an alleged Sandusky cover-up - former president Graham Spanier, former athletic director Tim Curley and onetime vice president Gary Schultz - have yet to be adjudicated.
Among the Penn State coaching candidates:
The lowdown: D6.
Staff writer Phil Anastasia contributed to this article.