"We just have to deal with it and keep moving on and other guys are going to have to step up to take part in our defense," he said.
In the Falcons' first two games, the defensive line has been one of the defense's strengths, as it recorded four sacks in Week 1. Now its depth will be tested and if Walker is to contribute, he'll have to learn the ropes quickly.
"Vance, I think he brings a lot of power, strength and size on the d-line," Johnson said. "I know he's excited, I just got done talking to him. I'm excited for him."