The NFL Players Association said Wednesday it sent a formal request to the league for information about Washington’s practice facility being searched by federal authorities last week.

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Head athletic trainer Ryan Vermillion was put on administrative leave for what a Washington spokesman called an ongoing criminal investigation unrelated to the team.

Two people familiar with the matter told The Associated Press that federal law enforcement officials, including agents from the U.S. Drug Enforcement Administration, served a search warrant at the facility last week. Another search warrant was served at a local home, according to one of the people.

The NFLPA said the situation "directly impacts player health and safety. The NFLPA insisted on language in our collective bargaining agreement that obligates clubs to adhere to all state and federal laws and regulations. We look forward to learning more so we can protect our players."

A league spokesman declined comment.

Washington returned to practice Wednesday without Vermillion, who did not travel for its game at Atlanta last week. Former trainer Bubba Tyer, who retired in 2009, was at the facility and on the field during practice.

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Asked Monday about Vermillion, coach Ron Rivera — who has worked with him for more than a decade dating to time together with Carolina — repeatedly referred to the team's statement.

"I’m not going to comment how I personally feel about what’s going on," Rivera said. "That would go beyond what I need to say."