NFL Media Insider Ian Rapoport recently reported that Crennel was still "looking at possibilities" and would have a better idea on his future after coaching in Saturday's East-West Shrine game.
Although Crennel and O'Brien are both members of the Bill Belichick coaching tree, they never spent time on the same staff in New England.
Crennel oversaw a top 10 defense in three of four years with the Patriots early last decade, but was never able to repeat that success in seven years with lesser talent on the rosters of the Chiefs and Browns.
The comforting news for Texans fans is that Crennel runs a 3-4 scheme, which means J.J. Watt -- the NFL's most dominant defensive player over the past two seasons -- will not be shoehorned into a position ill-suited to his strengths.
More Texans notes from McClain on Friday:
» The Texans have yet to hire an offensive coordinator, but O'Brien has already confirmed to McClain that he will call the plays in Houston. He gained respect in NFL circles for his play-calling in New England between the two Josh McDaniels stints running the offense.
» O'Brien won't show his hand with the 2014 NFL Draft more than four months away, but McClain is convinced the Texans will target a quarterback with the No. 1 overall selection. South Carolina defensive end Jadeveon Clowney won't be lining up opposite Watt in a dream pass-rushing tandem.
» O'Brien's task in mentoring a new quarterback will be easier thanks to his five seasons with the Patriots. He credits Tom Brady with teaching him a lot about the position and helping to get where he is today.