HOUSTON -- Houston Texans left tackle Duane Brown skipped the team's mandatory minicamp that began Tuesday, an absence that is thought to be contract-related.

"I don't have much to say on that. Obviously, Duane knows how I feel about him," head coach Bill O'Brien said. "We'd love to have him here, but at the end of the day, the guys who are here, that's who we're coaching."

Brown has two years remaining on a six-year contract, but there is no more guaranteed money left on the deal. He is scheduled to make a base salary of $9.65 million in 2017 and $9.75 million the following season.

Brown missed the Texans' voluntary OTAs earlier this offseason and can now be fined for his absence at minicamp.

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.