Johnson, the Eagles' first-round draft pick a year ago, will be suspended without pay for the first four games of the 2014 season for violating the NFL's policy on performance-enhancing drugs.
"In April while training, I mistakenly and foolishly put a prescribed medication in my body to help with a medical issue," Johnson said in a statement released by the Eagles. "I mistakenly failed to clear it with Eagles trainers and check the NFL list of banned substances. I am extremely sorry for this mistake and I will learn from it and be smarter in the future."
Johnson, the No. 4 pick in the 2013 NFL draft, started all 17 games, including the postseason, for the Eagles last year. The team benefited from having all five starters on the offensive line healthy and available for every game.
This year, the Eagles already know that won't happen. Johnson is eligible to take part in training camp and preseason games, but must sit out games against Jacksonville, Indianapolis, Washington and San Francisco.
"I would like to sincerely apologize to Mr. [Eagles owner Jeffrey] Lurie, [general manager] Howie Roseman, Coach [Chip] Kelly and his staff, my teammates and our amazing Philadelphia Eagles fans," Johnson said. "This will be very hard on me to not be battling with my teammates for four games, but I will be ready and better than ever when I return."
The Eagles, in a prepared statement, said: "We're very disappointed to learn of his suspension. 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."
The larger concern for the Eagles is whether Johnson relied on banned substances to fuel his growth from a junior-college quarterback to a 300-pound offensive tackle out of Oklahoma. The Eagles invested a $12.8 million signing bonus in Johnson after drafting him. Johnson's first four seasons of annual salaries -- totaling $2.1 million -- are also guaranteed.
Johnson's suspension will cost him $116,470 of his $495,000 salary for 2014. The more immediate concern for the Eagles is replacing Johnson at right tackle for a quarter of the season. The simplest and least disruptive solution would be to insert Allen Barbre at right tackle. Barbre, who played well in relief of left tackle Jason Peters last season, was rewarded with a three-year, $3.75 million extension in June.
Other candidates to replace Johnson: Right guard Todd Herremans could slide over with Barbre or another lineman replacing Herremans. Dennis Kelly, who had back surgery last season, will compete with Barbre in training camp. So could Matt Tobin, another young lineman the Eagles have in development.