Philadelphia Eagles offensive tackle Lane Johnson has lost his appeal of a 10-game suspension for violating the NFL's policy against performance-enhancing drugs for the second time.

Steve Zashin, Johnson's lawyer, told Albert Breer of The MMQB the ban was upheld Tuesday after an appeal that dragged into the regular season.

In August, Johnson blamed the NFL Players Association for failing to make clear which supplements are allowed, per ESPN.com's Phil Sheridan:

Every substance I've taken has been approved by the Aegis Shield app, which the NFLPA gives us. That's the only thing the NFLPA gives us to test our products.

I feel like the players have no rights. The supplement industry is not regulated, so you do not know what's in it. That's hard to believe, coming from a second-time offender, but I want that to be clear -- that the NFLPA does not stand up for players.

They don't check the supplements. They give us an app. Then if you call and ask them if you test positive for something they approve, it doesn't matter.

Johnson was suspended four games in 2014 for his first violation of the NFL's performance-enhancing-substances policy.

With the exception of that four-game suspension, Johnson has started every game of his four-year NFL career.

Allen Barbre will likely replace the 2013 first-round pick after the suspension was upheld. That would allow rookie third-round pick Isaac Seumalo to slide into a starting role at left guard.

Philadelphia is off to a 3-1 start, but losing Johnson for an extended period could hurt its playoff chances because of the adverse impact the suspension will have on protecting rookie quarterback Carson Wentz.