Brown apologized to the team's owners, coaches, fans and his teammates in a statement released by the NFL.
"I take full responsibility for putting myself in this situation," he said. "I unknowingly took a supplement tainted with a banned substance and now have to deal with the consequences. After reviewing the appeal process and speaking with legal counsel, I have decided not to appeal my suspension. I understand the rules and accept my punishment."
Texans general manager Rick Smith said the team was disappointed and called the suspension "a significant blow."
"Our players have to understand that they are responsible for what goes into their bodies and that they take risks anytime they use a supplement not approved by the NFL," Smith said in a statement released by the Texans. "Our head athletic trainer, head strength and conditioning coach as well as our team nutritionist have had many meetings and presentations constantly reminding our players about the dangers of the supplemental industry and risks associated with taking non-approved products."
Right tackle Eric Winston said the Texans have raised awareness among the players about the risks of using supplements since Cushing was punished.
"We talk about it, there are signs up in the locker room," Winston said. "There are all kinds of things, but it's an industry problem, too. They can put whatever they want in there. There's no regulation to it. Until there is something done about that, these things are going to happen."
Texans owner Bob McNair had no comment on the suspension, but Brown had started all 34 games since he was drafted, and the timing of his punishment could hardly be worse.
"You never want to have to deal with this too much," Winston said. "But that's the adversity we're dealt right now, and we're just going to have to keep moving forward as a team. Everyone is going to have to play better and just pick up the leftovers."
The Texans signed former starting tackle Ephraim Salaam after announcing Brown's punishment, according to Salaam's agent, Joby Branyon. Salaam, 34, played for Houston from 2006 to 2008.
"It feels good to be home," Salaam told KRIV-TV. "I plan to bring some veteran leadership. You always want to have guys who have been through the fires."
"I feel sad and disappointed to hear about Duane and his situation," Butler told KRIV-TV. "I know Duane will serve his four-game suspension and will come back even more hungry than before.
"The team has to go on," Butler added. "Coach (Gary) Kubiak and (offensive line coach) John Benton have given me a great opportunity to fill his shoes."
Cushing, the reigning Associated Press Defensive Rookie of the Year, was suspended in May for testing positive for HCG, a fertility drug that is on the NFL's banned substances list.
Cushing met with several doctors over the summer and said some concluded that his positive test resulted from overtraining. McNair met with NFL Commissioner Roger Goodell in New York to plead his case, but the league upheld Cushing's suspension.
Copyright 2010 by The Associated Press