The game at Lincoln Financial Field is the most important preseason game yet for Johnson. He will play more than he has in the previous three games, and it will be his final game-like action until after Week 4.
"It's actually going to be four quarters I'm playing, and I'll be able to execute both halves instead of just one or two quarters," Johnson said. "That will be a big deal."
Coach Chip Kelly said Johnson's presence on the second-team offensive line has bolstered that group, but he has not felt compelled to play Johnson with the starters because the focus is getting ready for the opener.
Working with the backups also has improved Johnson's communication skills. Playing next to veteran Todd Herremans last season, Johnson was able to use Herremans as a crutch. On the second team, Johnson makes the calls.
"I think, from that standpoint, I'm a lot better than I was last year," Johnson said.
The guard said he has been playing "pretty well" this summer. But he worries about rust gathering during his time away. Johnson admitted it's difficult maintaining "football shape" when not playing football. He is not allowed to visit the team's facility or have contact with any coaches, so Johnson will be on his own.
"It's just tough mentally, not being around here, staying on top of the playbook," Johnson said. "That's going to be tough, not practicing. . . . I'm going to have to find something to do to keep in shape."
Johnson originally planned to stay in the area and train in Cherry Hill. He changed those plans this week, prompted by strength and conditioning coach Josh Hingst, who wants Johnson to train at the Athletes' Performance Institute in the Dallas area. Johnson will work with other football players using the facility. He does not know which players will be there, but Johnson said he will be able to work on pass protection.
Most important, Johnson thinks he can benefit from the institute's nutrition program.
Johnson said he will speak with Herremans after each game to rehash what happened. He will also keep up with the team's practices and meetings on his iPad.
At the beginning of training camp, Kelly said that the Eagles would do what they could to help Johnson's development in August. Once the season comes, "the ball's in [Johnson's] court," Kelly said.
Thursday's game will be a last look at one of the team's most promising players before he spends September in Dallas. Kelly still has not revealed what will happen when Johnson returns.
"We've got four games of Allen playing with us, and hopefully we can keep all five of those guys healthy up front," Kelly said. "And then bring Lane back and work him into the mix and see how it fits at that point in time."