April 13 (UPI) -- Quarterback Mark Sanchez has been suspended for four games for violating the NFL's policy of performance-enhancing substances.
The league announced the suspension on Friday.
Sanchez responded on social media, saying that he was "blind-sided" by the suspension.
"The NFL has informed me that I have tested positive for a substance on the banned substance list," Sanchez wrote on social media. "I was blind-sided by the news and I want to say unequivocally that I have never cheated or attempted to gain a competitive advantage by using a banned performance enhancing substance."
"During the past nine years as an NFL player I have been subject to 73 drug tests -- an average of over eight tests per season -- and all but one have been clean. I have taken the same regimen of supplements for the past five years without any issues. The timing and results of my tests establish circumstances of unknowing supplement contamination, not the use of performance enhancing drugs."
Sanchez, 31, is a free agent. The No. 5 overall pick in the 2009 NFL Draft played the first four seasons of his career with the New York Jets, before being signed by the Philadelhpia Eagles in 2014. Sanchez was traded to the Denver Broncos in 2016, before being signed by the Dallas Cowboys six months later.
The USC product completed 55.6 percent of his throws for 93 yards, zero touchdowns and two interceptions in two appearances in 2016 for the Cowboys. Last season, Sanchez sat behind Mitchell Trubisky and Mike Glennon on the Chicago Bears' depth chart.