Johnson entered the game just 4-for-38 in August, with four walks and 13 strikeouts in 11 games. He has spent a fair amount of time in the cage, hitting off a tee and flips, and taking batting practice.
"[I'm] just staying on the ball a little better and staying up top, not dipping, not coming under, staying shorter," Johnson said.
Manager Kirk Gibson said that Johnson's biggest challenge will be getting his timing down against big league pitching.
"You hope that he can have some success so he can validate the work," Gibson said. "That always helps."