Though Joyner said he believed O'Brien had intentions of staying with the university "for the long haul," he seemed understanding and wished the 44-year-old well.
"Bill always operated under the assumption that he was going to be here for an extended period of time," Joyner said about O'Brien, who went 15-9 and weathered harsh NCAA sanctions while at Penn State. "So that will be very important in our efforts going forward here as well, and, again, I reiterate things change sometimes. You can't predict, and I think Bill just had an opportunity presented to him that was one that he couldn't pass up."
Joyner leads the six-member search committee and is joined by Tom Poole, vice president for administration; Charmelle Green, associate athletic director and senior woman administrator; Linda Caldwell, faculty athletics representative; Bob Warming, men's soccer coach; and Wally Richardson, football letterman's club director and former Penn State quarterback.
Joyner said he and the committee hope to move quickly, as he noted he thinks a hire will be made in a matter of days as opposed to weeks. Names of potential successors already have started circulating, and while Joyner did not give any names, he said Penn State has already been contacted by "a number of very prominent head coaches."
He was asked if having connections to Penn State was part of the criteria for the next coach, and while he said that wouldn't hurt, it is not necessary.
"It's not a requirement going forward, but it's something that will be part of the selection or it will be a thought process in the selection of the next great football coach at Penn State," Joyner said. "But our job is to select, regardless of someone's history, as long as it's a positive history, our job is going to be to select the next great head football coach at Penn State and to get the best football coach available for Penn State University."
In the meanwhile, Johnson will try to keep the current team and 2014 recruiting class together. Johnson, who is widely regarded as one of the best recruiters in the Mid-Atlantic area, has been at Penn State since 1996 and is the only holdover remaining from Joe Paterno's staff. Joyner called the coach who has been in charge of the Lions' defensive line for 15 seasons "extremely stable."
"Larry Johnson is a tremendous individual, as you all know," Joyner said. "He means a lot to Penn State, and he's meant a lot to these players over the years. So we're very, very fortunate to have a man of Larry Johnson's caliber to be able to act as the glue right now."
A handful of players, including defensive end Deion Barnes, tweeted they thought the man they refer to as "LJ" would be a good choice for the full-time job as head coach. When Joyner was asked about that possibility, he said Johnson was welcome to get in the mix, if he desired.
Joyner - who noted he had not directly spoken with players since O'Brien's departure - was also unsure about the future of the rest of Penn State's coaching staff.
Some assistants may join O'Brien in Houston, and running backs coach Charles London said he didn't have any concrete plans for where he'd end up, but didn't rule out following O'Brien or staying at Penn State. Pennlive.com reported Wednesday that wide receivers coach Stan Hixon would be part of O'Brien's staff with the Texans.
In addition to assistant coaches having clouded futures, so too do the bosses of whomever Penn State's next head coach will be. School president Rodney Erickson will be out of office by June, and Joyner might be as well (though he didn't say anything for certain when asked). Even with the uncertainty of the administration, Joyner said he did not think it would be a problem in the search.
"Transitions occur in programs all over the place at different times, and athletic programs survive and go on and move forward," he said. "My answer to that would be that Penn State has a great tradition of great presidents and administrators and I would say to any perspective coach, Penn State would continue with that great tradition, no matter who is at the helm."
Bill O'Brien is not the only key piece who will not be back with Penn State next season.
Two-time all-Big Ten wide receiver Allen Robinson will declare for May's NFL draft, foregoing his senior season, Penn State announced. Robinson holds Penn State single-season records for catches and receiving yards, and the 6-3 wideout finished his collegiate career with 177 catches, 2,479 yards and 17 touchdowns.
"It was a great honor to play at Penn State," Robinson said in a press release. "I am blessed to have played with, and for, the people in the Penn State football program. This is a decision that I believe is best for my family, and I wish all the best to the university and all my teammates."
Robinson has the chance to become Penn State's first selection in the first round of the NFL draft since the Miami Dolphins took defensive tackle Jared Odrick 28th overall in 2010. CBSsports.com ranks Robinson as the fourth-best receiver in the draft, and projects the Southfield, Mich., native as a first- or second-round pick.
On Twitter: @SPianovich