NASHVILLE, Tenn. -- Titans linebacker Gerald McRath has dropped his appeal and accepted a four-game suspension from the league for a violation of the NFL policy on performance-enhancing substances, he said.
But he maintains the positive test is from a tainted supplement he's continuing to attempt to track.
"You can read the labels and you can look at everything and they don't have anything written on there but the batch that I had could have been tainted," he said. "But you don't know that because I don't have the batches anymore ..."
"The image part is moreso difficult dealing with than actually the four-game suspension ... I'm really trying to put the emphasis across: I'm going to take my four-game suspension. I don't want anybody to say, 'He got off, he probably was taking something.' "
McRath, a fourth-round draft pick out of Southern Miss last year, has been working as a starting outside linebacker this offseason.
His absence for the first four games likely opens room for David Thornton, who has battled injuries, to get back on the field. Thornton's been a starter the last three years. The Titans open with Oakland, Pittsburgh, the New York Giants on the road, and Denver.
Titans coach Jeff Fisher said he was aware of the appeal process.
"Gerald, like most of his teammates, is very, very conscientious about [what he takes]. There are situations where even though you think you are taking a product that's safe, oftentimes there are contaminated batches," Fisher said. "... I believe in my discussions with Gerald that there was nothing intentional."
McRath said he has not taken any supplements since February, has spent about $6,000 on his own testing and will test anything he would take going forward before taking anything again.
McRath's suspension starts Sept. 4, and he cannot return to the roster until Oct. 4.
Paul Kuharsky covers the AFC South for ESPN.com. Information from The Associated Press was used in this report.