He noticed a difference in energy while playing his first game with the D-backs, too.
"It's a sense of urgency," Johnson said. "Guys want to get on base. Guys want to keep the line moving. Every out, every pitch matters. Guys take this pretty seriously, and that's what I'm going to do. I'm just going to follow that lead."
Baseball players are professionals, paid to play hard, regardless of the setting or the circumstances. But there are several aspects of the game that change dramatically in a clubhouse when a team is in contention.
The first thing Johnson noticed was the scoreboard-watching. While the third-place D-backs were beating the second-place Dodgers, he heard a teammate mention the score of the Giants game.
"That kind of shocked me, because I'm not really used to that," Johnson said. "It's intense out there, especially playing [the Dodgers]."
But the differences between clubhouses don't stop at monitoring scoreboards.
Dodgers manager Don Mattingly spent about half of his stellar playing career toiling in the bottom half of the American League East, grinding out the days for the Yankees in the late '80s and early '90s. But he took part in down-to-the-wire playoff races in 1985 and 1995, and he may be poised for something similar this season.
"It's just a very different dynamic when you're playing for something," Mattingly said. "It's more of a group when you're playing for something as a team that you've worked for. You came to Spring Training, and you've got a group of guys that have been together all year and some of them for a while, and you've got a chance to play for something.
"That's totally different than if you're 20 games out and there's really nothing to play for and you're just putting up stats. It's a lot tougher to play in the scenario where it gets to be individual. It's not nearly as much fun."
The argument of individual performance was brought to the forefront last season, when the Brewers' Ryan Braun and the Dodgers' Matt Kemp were locked in a battle for the National League Most Valuable Player Award.
One school of thought said that Braun's performance was more impressive because he was under the intense pressure of a pennant race, while Kemp's Dodgers were also-rans. Another said that his task was easier because he went to the park every day with a clear objective. (This season he is on the other end of that discussion, as he has put up similarly gaudy numbers but the Brewers have fallen out of the NL playoff picture.)
Mattingly was asked if it is easier to play and put up MVP-caliber numbers for a team in a race.
"When you're winning?" Mattingly said. "No question."
In a matter of minutes last month, Hanley Ramirez went from one extreme to the other, when he was traded from the struggling Marlins to the Dodgers.
"It's way different," Ramirez said. "You have to win every day. That's one of those things that I like -- that kind of pressure that you get to put on yourself, and being on the same page with all those guys in here.
"You walk into the clubhouse, you see all the smiles, everybody's together, pulling for each other. Those are the little things you look for."
Catcher A.J. Ellis quickly dismissed the notion that the Los Angeles clubhouse has changed this season, and his manager backs him up on that. Ellis says the players are preparing the same way they did last season, when the Dodgers were fighting to get to .500.
"I don't think we're quite at the stage where we can do full-fledged scoreboard-watching," Ellis said. "We still have business to take care of for ourselves. Maybe postgame we'll check and see what everyone else in the division did. But right now it's about us, and it's about us winning games."
The Dodgers may not yet be keeping constant tabs on the Giants and D-backs and other Wild Card contenders just yet. But you can bet those clubhouses will have a much different feel in the coming weeks.