NFL players who refuse to cooperate with the league's investigation into claims made in an Al Jazeera America report on steroid usage will be subject to suspension, the NFL warned in a sternly worded memo sent to the NFL Players Association on Monday.
In the letter, obtained by ESPN.com, the NFL imposes an ultimatum requiring Packers linebackers Clay Matthews and Julius Peppers, Steelers linebacker James Harrison and former Packers linebacker Mike Neal to meet with league investigators before Aug. 25 or face discipline.
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"For those players whose interviews do not take place on or before (Aug.