The Seattle Seahawks lead the NFL in suspensions for performance enhancing drugs since Pete Carroll became head coach in 2010.

Bruce Irvin became the fifth member of the Seahawks to receive a suspension on Friday.

The total does not include the overturned four-game ban for Richard Sherman at the end of last season.

The Denver Broncos and New York Giants have received four suspensions apiece.

The San Francisco 49ers are amongst 10 teams to have zero suspensions.

Bruce Irvin has been suspended for four games for violating the NFL's performance-enhancing substance policy.

Irvin will miss games against the Panthers, 49ers, Jaguars and Texans.

"I want to apologize to my teammates, coaches and Seahawks fans for making a mistake when I took a substance that is prohibited in the NFL without a medical exemption," Irvin said in a statement.