The team doesn't comment on transactions until after they're made official with the NFL.
The Penn State head coach reportedly interviewed with the team on Decmeber 26th, and has been considered "the overwhelming favorite" for the position over the course of the last week.
The Texans fired Gary Kubiak on December 6, and defensive coordinator Wade Phillips took over as the interim head coach for the final three games of 2013. Phillips reportedly interviewed for the job last Thursday evening.
In the press conference announcing the Kubiak firing, team founder/chairman/CEO Bob McNair said the Texans' ideal candidate had experience as a coach in the NFL, as well as head coaching experience.
O'Brien, by virtue of the last two years, combined with his five-year stint as an assistant with the Patriots, met those qualifications.