STATE COLLEGE, Pa. (AP) -- Bill O'Brien is leaving Penn State's reclamation project in his successor's hands. Less than two years after replacing Joe Paterno as coach of the Nittany Lions, O'Brien will return to the NFL as coach of the Houston Texans, leaving a proud Penn State program in peril once again. Two people familiar with the negotiations, speaking to The Associated Press on the condition of anonymity because an official announcement hasn't been made, said O'Brien reached an agreement Thursday night to coach the Texans. O'Brien bolted Penn State and a slew of players who pledged their commitment to the program in its darkest hour for the big bucks tossed his way by an NFL team desperately seeking to become contenders in the AFC. O'Brien, a former offensive coordinator for the New England Patriots, took on perhaps college football's toughest job in January 2012, adopting a program that was rattled by the Jerry Sandusky child sex abuse scandal. And despite a lack of scholarships, a bowl ban, an overall sense of doom, and many player defections from the late Paterno's final roster, O'Brien led the Nittany Lions to two winning seasons (8-4, 7-5), restoring some tempered enthusiasm in Happy Valley. But the Nittany Lions are back to the drawing board this week, after losing O'Brien in a similar circumstance that he turned down last year. After his debut season, O'Brien interviewed with the Jacksonville Jaguars and Cleveland Browns, among others, only to stay in State College. But the Texans' job was too good to pass up some 12 months later. Whereas the Browns and Jaguars were in the midst of complete overhauls, from the front office to the locker room, Houston is viewed as one of the best jobs in the NFL. The city is crazed for its Texans, there is plenty of talent on the roster -- especially on defense -- and the AFC South is a division that seemingly is up for grabs every season. The NCAA penalties handed down in July triggered a clause in O'Brien's contract that extends his deal the length of any sanctions handed down to Penn State, so O'Brien's deal now runs through 2020. O'Brien received a restructured deal last year, after he decided to stay. Though the contract was set to run seven more seasons, a buyout clause will kick in to allow for his exit. In the eyes of Nittany Nation, though, those are all logistics now. What O'Brien will make elsewhere, and what he's inheriting at the game's highest level, mean little to a fan base and community that has wrapped its arms around not only him, but his family as well. O'Brien tackled the challenge of replacing Paterno -- at a critical time in the program's history no less -- with ferocity and passion. He changed the culture of the program by, among other things, instituting names on the backs of the jerseys, playing loud music during practice to fire up the players and prepare them for hostile environments, and overhauling the team's offseason weight training program. All along, he was lauded for his efforts. At the same time, though, he always paid homage to Paterno, and the legacy he built with the Nittany Lions. He said and did the right things, and made the absolute most of the 24 games he was given at Penn State. Which, in the end, made him even more marketable to the NFL. Of course, that is little consolation to Penn State. The Nittany Lions need to prepare for life in the expanded Big Ten next season, and need a new leader to help them do so. While Penn State is still a destination job in college football, the roadblocks are still many as the program continues to build back up, post-Sandusky: -- Though there is talk that this may be reduced at some point, Penn State's bowl ban has not been lifted yet, and runs through the 2015 season. -- Though some scholarships have been restored, there is not the full allotment that other Big Ten schools -- including new members Rutgers and Maryland -- have at their disposal. -- Recruiting season is in full swing right now, a time when anxious high school seniors may cross the Nittany Lions off their list. -- And then, of course, there's the remnants of the scandal still lingering. The trials of former Penn State president Graham Spanier, athletic director Tim Curley and vice president for finance Gary Schultz -- all accused of trying to cover up the scandal at the time -- are still to be completed. All of this will cloud a field of candidates likely to include many from the college ranks, as well as NFL head coaches and coordinators. Greg Schiano, for instance, has Penn State ties and may want to return to college after two forgetful seasons with the NFL's Tampa Bay Buccaneers. While at Rutgers, Schiano was viewed as an Eastern recruiting expert, who built the Scarlet Knights into a consistent bowl-ready program by landing players from New Jersey down to Miami annually. Schiano would likely be received well in State College, but he is not O'Brien. The coach, who helped lead the Patriots to the Super Bowl in 2011-12, arrived in Happy Valley with sterling credentials; apprenticeships coaching at Brown, Georgia Tech, Maryland and Duke, followed by five years as an NFL assistant on Bill Belichick's staff. He won games, he won over players, and he did so, traditionally, with a stern look on his face. "A few days before we announced the hiring, I was watching a Patriots game, and I see Bill walk down the sideline, stop in front of Tom Brady, and start yelling," Penn State athletic director Dave Joyner said. "And I'm thinking, 'He's yelling at Tom Brady! Tom Brady! Who's maybe only the best quarterback ever!' Right about then, I said to myself, 'We got the right guy. He's plenty tough enough.'" His teams at Penn State took on that identity. After a lackluster start -- O'Brien lost to Ohio and Virginia to open his career -- Penn State rattled off five straight wins, and finished the year with a rousing 24-21 win over Wisconsin at home. This season, the Nittany Lions started off better -- wins over Syracuse and Eastern Michigan opened the year -- but dealt with inconsistency issues along the way. All that said, like his first season, O'Brien closed with a flurry, defeating the Badgers, this time in Wisconsin, 31-24, to close out the campaign. "We've said the same thing for two years," O'Brien said after the finale. "Our guys, they practice hard, and they love to play." It showed. But it went beyond just the wins and losses. O'Brien, a players' coach if there ever was one, developed bonds with his roster, but never let that get in the way of the task at hand. He needed to grow college football players into Penn State players, and in many cases, he was successful. At a time when the program he inherited was undercut by the defections of the team's best running back, top receiver and its front-line kicker -- more than a dozen players in all -- he just kept working with what he was given. When Silas Redd took most of Penn State's running game with him by transferring to Southern California, O'Brien drew on his experience at New England and turned former walk-on quarterback Matt McGloin into an NFL-ready one. After kicker Sam Ficken missed four field goals, including a potential game-winner, O'Brien refused to blame the inexperienced backup and instead had the Nittany Lions try to convert fourth downs in a variety of unlikely situations. His players loved that, and returned every show of loyalty in kind. "When those things first happened, Coach told us flat-out we wouldn't come out on the other side of the experience unscathed," said John Urschel, a fifth-year senior and All-Big Ten guard. "But the other thing he promised us was an experience we'd never forget." It's safe to say most of the fan base will never forget O'Brien's tenure either. Whether or not they forgive him for leaving, is another story. But for now, the focus in Happy Valley needs to be on moving forward with someone new, maintaining a sense of calm inside the program, and preparing for unexpected change. In other words, exactly what the program did just two years ago. _____ AP Sports Writer Kristie Rieken in Houston contributed to this report.