Aaron Judge explains why he chose to stick with baseball over pursuing a professional career in basketball or football. Tune in to Sunday Night Baseball for the full interview. (1:14)

MINNEAPOLIS -- Aaron Judge uses dirt to clear his mind.

Often, when the New York Yankees rookie right fielder is at bat, he'll reach down to pick up some soil around home plate. He does it subtly enough that even many of his teammates said they hadn't noticed. It is part of his routine, reminding himself to focus on the next pitch, not agonize over the last one.

"For me, it's just a way of slowing things down, taking an extra two or three seconds to grab some dirt," Judge said. "For me, all my negative thoughts that I have about, 'How did you miss that pitch? Why did you miss that pitch? You shouldn't have missed that pitch.' I just kind of sit there and kind of crush it up, and once I'm done doing that ... I just kind of toss it aside.

"For me, that's basically tossing all those thoughts out, like, 'Hey, that's done with. That's over with now. Start fresh and get back in the box and get back to your positive thoughts and get back to your approach.'"

Manager Joe Girardi is one of the few people in the Yankees' dugout who noticed Judge's habit, but he didn't know the reason for it. The manager thought Judge might do it for a better grip. That's true, in a way -- just a better grip on his mind, not his bat.

"The mental game is what separates the good players from the great players," Judge said. "So anything I can do to get that mental edge to help me stay my best, I'm gonna try and do it."

It has worked for the 6-foot-7, 282-pound Judge, the leading candidate for the American League MVP and Rookie of the Year awards. But after winning the Home Run Derby and being the center of attention at the All-Star Game in Miami, Judge has begun the second half picking up more dirt than usual; he's in a 1-for-21 slump. The one hit went about 10 feet, though in fairness, he was robbed of a home run by Jackie Bradley Jr. at Fenway Park on Sunday.

Judge and Girardi said they aren't concerned with the slow start, attributing it to a lull that hits all major leaguers over a 162-game season.

"He continues to have that smile on his face and plays loose," Girardi said. "I haven't seen him press."

Overall, Judge is hitting .311 with 30 homers and 66 RBIs. He's still so feared that, despite his slump, Twins manager Paul Molitor intentionally walked him in the eighth inning Monday night in a tie game with a man on second and no one out.

After a historic first half and a Home Run Derby title, Aaron Judge has gone 1-for-21 since the All-Star break. But he has a ritual -- one he performs in plain view, but until now was unknown even to many of his teammates. Winslow Townson-USA TODAY Sports

Last season, when he hit .179 and struck out in 42 of his 84 at-bats after an August call-up, Judge never changed his personality. He also never forgets, as he keeps ".179" in the notes he studies before every game.

Judge started digging in the dirt while in college at Fresno State, after reading "Heads-Up Baseball," a book co-authored by sports psychologist Ken Ravizza. Judge has read the book again and again, and has added the sequel, "Heads-Up Baseball 2.0," to his library. The dirt is the most apparent effect the books have had on the 25-year-old Baby Bomber.

"Sometimes, I don't need it," Judge said. "Sometimes, I'm mentally strong enough to say, 'Hey, you missed it, let's get back in there, let's go.' Other times, I need that extra second to slow everything down."

Besides the dirt, Judge has other quirks in his routine. He starts each game with two pieces of Dubble Bubble gum, chewing it until he makes an out. When he runs in from right to end an inning, he almost always waits for his center fielder and left fielder to enter the dugout first so he can give them some encouragement.

Judge, with an assist from the Yankees, his family and his agents, has tried to limit off-the-field distractions. As his fame has grown, there is more demand for his time, but Judge is turning down all extraneous requests.

"The mental game is what separates the good players from the great players. So anything I can do to get that mental edge to help me stay my best, I'm gonna try and do it."

"You just put your blinders on because I have a job to do on the field," Judge said. "My main focus is: 'What can I do today to help the team win the ballgame?' You have those blinders on. It helps you focus.

"I have a short time to play this game. I'm trying to get every ounce of it out of my body. I try to do everything for this team and this game that I can. I'm not going to play this game for 100 years. Whatever I have to do to make my career last as long as I can and help this team be successful, I'm going to do it. I don't need to be doing any extra stuff right now. When I'm 40, 45, 50, maybe I can do that kind of stuff. Right now, it is just keeping your blinders on and taking care of business."

That means reaching for some dirt when his mind isn't right. All-Star pitcher and teammate Luis Severino noticed the habit and knew exactly why Judge did it.

"It is something so not to have a lot of pressure on you," Severino said.

On the other hand, third baseman Chase Headley hadn't picked up on Judge's routine. Headley said he simply takes a deep breath when he wants to calm himself down at the plate. But when he was told what Judge does, he said he might consider it, given what the rookie has accomplished.

Said Headley: "If you see me picking up dirt, you'll know why."