In announcing Thursday the creation of a six-member search committee to find a new head coach, Joyner acknowledged O'Brien's resignation and confirmed that longtime defensive line coach Larry Johnson has been named interim head coach to keep together current players plus the 2014 recruiting class.
At a Beaver Stadium news conference, Joyner said the search committee will operate rather quickly compared to the lengthy search that resulted in O'Brien's hiring in 2012, nearly two months after Joe Paterno's firing.
"We expect this search to be very timely," said Joyner, who will chair the panel. "Our anticipation is that we'll be counting this in a matter of days rather than weeks."
The search committee does not include any members of the university's board of trustees. It does include former Nittany Lions quarterback Wally Richardson, director of the Penn State Football Letterman's Club.
Joyner revealed that his office had been working with O'Brien and his representatives "to make his contract and his arrangement here as advantageous as we could possibly do." In the end, the lure of the NFL, in which O'Brien worked for five seasons before taking the Penn State job in January 2012, was too great.
"I believe that Bill O'Brien was presented with just a tremendous opportunity - one that, for his family and friends, he just could not pass up," Joyner said. "So I believe he always had Penn State's best interests at heart and this is just something that came up that he couldn't pass up. We wish him well."
So after having Paterno as its head coach for 46 years, the university now must conduct another search two years after the one that brought O'Brien to Happy Valley. Joyner said interest has been strong in the process' early stages, although he would not give specifics.
"We're not going to give out details of where we are in the process until the end," he said, "but we have been contacted by a number of very prominent head coaches or their representatives. We will work through the appropriate process for discussions with them in the near term."
Reported candidates for the position include those with Penn State ties, such as Tennessee Titans coach Mike Munchak, University of Miami coach Al Golden, and former Rutgers and Tampa Bay coach Greg Schiano, and those without - Vanderbilt coach James Franklin and San Francisco 49ers offensive coordinator Greg Roman.
Joyner said that having a Penn State connection is not a requirement for the new coach but that it would be "a thought process in the selection." Still, he said he wants to find the best available coach "regardless of someone's history, as long as it's positive history."
Joyner indicated that he is not concerned about Penn State's impending change of president. Rodney Erickson will be leaving his job no later than June 30, and the new president may bring in his or her own athletic director to replace Joyner.
"Penn State's got a great tradition of great presidents and administrators," Joyner said, "and I would say to any prospective coach that Penn State will continue with that great tradition."
As for Johnson, who just finished his 18th year on Penn State's coaching staff and is the only holdover from the Paterno years, he will be interviewed if he desires to be, Joyner said. Johnson is a strong favorite among Penn State players.
"We're very, very fortunate to have a man of Larry Johnson's caliber to be able to act as the glue right now," Joyner said. "Coach Johnson is a tremendous individual, and if he wants to get into the mix [of candidates], he'll be very much welcome."
In a statement, Johnson said he was "humbled by the confidence that Penn State has bestowed upon me during this critical time for the football program and honored to do my part to help Penn State."