The move had been rumored earlier this week, when sources told Mortensen the two sides were working on a deal to make O'Brien the Texans' next head coach. O'Brien will replace Gary Kubiak, who was fired earlier this month.
Houston is set to introduce O'Brien by this weekend.
O’Brien, an assistant with the New England Patriots from 2007 to ’12, wrapped his second season at Penn State this fall. The coach was the Big Ten’s Coach of the Year in 2012, when he replaced longtime coach Joe Paterno following the Jerry Sandusky child abuse scandal. In the thick of heavy NCAA sanctions, O’Brien went 8-4 in his first season in Happy Valley and 7-5 in 2013.