The two sides could not come to an agreement on a long term contract, which ultimately led to Clowney being moved for a third-round draft pick and outside linebackers Barkevious Mingo and Jacob Martin from Seattle.
"We think very highly of Jadeveon Clowney. Let’s be clear about that," O'Brien said at Monday's press conference. "He’s a good football player. He made a lot of great plays for us. He had a lot of good Sundays for us, no doubt about it. But we think we made the best decision for him and we feel like we made the best decision for our organization moving forward."
Clowney is due $15.9 million playing under the franchise tag in 2019. The Texans are paying his $7 million signing bonus while the Seahawks pick up the remainder of his salary.
Clowney made the Pro Bowl in each of the last three seasons, recording 18 1/2 sacks and 37 tackles for loss in the past two seasons.
When asked if the Texans defense is better after trading Clowney, O'Brien said "I think we have a good defense."
"I think we have a strong front. I think our secondary's improved everyday. Some new guys in the secondary. I think the communication's gotten better. I think Bradley Roby, a new addition, has had a good camp. I think (Tashaun Gipson) been out a little bit but he'll be back there tonight.
"I think (safety) Jahleel Addae has been a good addition. (Jonathan Joseph) as everybody knows is a Houston mainstay. He's a hell of a player. I think Brian McKinney is a very good player. I think Zack Cunningham, and Whitney Mercilus and JJ Watt and DJ Reader and Dylan Cole, the list goes on and on. I think we've got a good defense."