Pittsburgh Steelers right tackle Marcus Gilbert has been suspended for four games without pay for violating the NFL's performance-enhancing drug policy.

The Steelers announced Gilbert's suspension on Monday, meaning quarterback Ben Roethlisberger will be without one of his starting pass protectors for much of the final stretch of the regular season.

"We are disappointed that Marcus Gilbert has been suspended four games for using performance-enhancing substances. He will not appeal the NFL's decision," Steelers general manager Kevin Colbert said in a statement.

"The suspension is effective immediately, and he will not be permitted in the building until after the suspension has concluded following our game on December 17."

The ban is the fourth multiple-game suspension in three years for the Steelers after wide receiver Martavis Bryant and running back Le'Veon Bell missed time during the 2015 and 2016 seasons.

Gilbert was selected out of Florida by the Steelers in the second round of the 2011 NFL Draft. He will miss matchups against the Green Bay Packers, Cincinnati Bengals, Baltimore Ravens and New England Patriots while serving the suspension.

"I apologise to my team-mates, coaches and the entire Steelers family," Gilbert posted on Twitter. "Regretfully I inadvertently took a banned substance. I promise to come back in great shape and will be ready to play when my suspension is over."

Gilbert will be eligible to play again when the team visits the Houston Texans for a Christmas Day showdown before wrapping up the regular season at home against the Cleveland Browns on New Year's Eve.