Philadelphia Eagles offensive tackle Lane Johnson has been suspended for the opening four matches of the NFL season for violating the league's policy on performance-enhancing substances.

The 2013 Draft pick has stated that he took prescribed medication which caused his failed drug test and he has since apologised to the organisation for the incident.

"We're very disappointed to learn of his suspension," the Eagles said in a statement. "We have spoken to Lane about the details of the suspension. He understood what he did wrong and took full responsibility.

"The key for him, however, is to learn from that mistake and move forward with his preparation for the 2014 season."

Johnson will miss fixtures against the Jacksonville Jaguars, the Indianapolis Colts, the Washington Redskins and the San Francisco 49ers before returning to their active roster on September 29. He is permitted to practise fully during pre-season training camp and is also available for exhibition matches.