The Texans placed him on the reserve/did not report list on Tuesday. Brown, 31, now can be fined $40,000 for each day of training camp he misses. The Texans' training camp officially begins Wednesday at The Greenbrier resort in West Virginia.
"I have talked to Duane. And I don't know that this is a holdout. There's no contract dispute. Duane's under contract for two more years. That's our position. We're here to get our football team ready for the season, and he should be a part of it. ... Here's an important member of our team, and he ought to be here," general manager Rick Smith said Tuesday.
The risk he is taking to try to make more money has already resulted in lost money.
Brown's deal with Houston included a $250,000 de-escalator clause if he did not participate in a requisite number of workouts. Brown triggered the de-escalator, and his base salary has dropped from $9.65 million to $9.4 million, a league source told ESPN's Field Yates.
He has two years remaining on his six-year contract, but there is no more guaranteed money left on the deal.
Brown, who was named a Pro Bowl alternate last season, is entering his 10th NFL season. He anchors a Texans offensive line that currently does not have a starting right tackle after the team put Derek Newton on injured reserve.
ESPN's Sarah Barshop contributed to this report.