Washington Redskins defensive end Jarvis Jenkins has been suspended four games for violating the NFL's performance-enhancing drug policy.

Jenkins can practice throughout the preseason and play in preseason games, but his suspension starts prior to the start of the regular season and runs through Sept. 30.

“When I learned that I tested positive for a substance that is banned under the NFL policy, I was shocked and confused,” Jenkins said in a statement released by the Redskins. “It’s an obscure substance that I’ve never even heard of, and I still don’t know how it got into my body. My only guess is that it came from one of the supplements I was taking around the time of the test, even though none of them listed anything banned.”

Under NFL policy, a player is responsible for everything that he ingests.

So, rarely, does the league accept any excuses when it comes to the performance-enhancing drug policy

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Aaron Wilson covers the Ravens for The Baltimore Sun.