Johnson, who hit a go-ahead RBI single in Sunday's eventual 3-2, 12-inning loss to the Pirates, is batting an even .300 with 20 RBIs on the season.
"You can't be [too comfortable]," Johnson said. "My experience has taught me that. I'm going to keep working, and the main thing is we're winning some ballgames. We need to get to that .500 mark and we'll go from there."
Johnson has been working all season on being more selective, and manager Brad Mills said finding the right approach is a never-ending process.
"It's a situation where he's still fining where he's at, finding where that strike [zone] is and finding what pitches he can handle and what pitchers he can't handle," Mills said. "Those are things he's still going through. For this stretch of close to two years, I've tried to hit him sixth and seventh most of the time to kind of take [pressure] off. He's got the bat speed to really do some damage."