"We'll put him in there and get him going," Shurmur said.
"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 was the top pick of the Eagles in 2013 and started all 16 games, rating as a great run blocker but a poor pass blocker according to ProFootballFocus.com.
The Eagles' first four games are against the Jaguars, Colts, Redskins and 49ers.
Men's New Era Midnight Green Philadelphia Eagles 2015 NFL Draft On-Stage 59FIFTY Fitted Hat Shop Now!