Cardinals inside linebacker Daryl Washington, one of the team’s brighter young stars, has been suspended for the first four games of the 2013 season for violating the NFL’s substance abuse policy.

It’s unknown what Washington did to warrant the suspension.

“I was always taught that when you make a mistake, you admit it, learn from it and face whatever consequences there are,” Washington said in a statement released by the team. “I take full responsibility and I understand that I let down my teammates, the organization and fans. I apologize for that and promise that no one will work harder to make up for it.”

Last September, Washington signed a six-year contract extension that included $32 million of new money.

That contract includes a $10 million option bonus due next March, which gives the Cardinals time to evaluate Washington throughout this season.

That clause might indicate that Washington had previous problems, and the Cardinals knew about them.

“Adversity and dealing with it is part of the business,” coach Bruce Arians said in a statement, “but when it’s avoidable like this, it’s particularly tough.

“One of the biggest things we preach is accountability; Daryl knows that and our team knows that. We will deal with this and others will have to step up until he’s back. I’m confident they will.”

Washington’s suspension is not for performance-enhancing drugs. The four-game suspension likely means that he was in the second of three phases of the NFL program, an indication that there were previous problems.