Why the change? Because Ozuna sustained a season-ending thumb injury, which required surgery, last July.
Whenever he gets hurt, he feels the number is cursed, and he changes things up.
"If I get hurt, I change my number," Ozuna said. "Then I'll get more luck."
The myth that 13 is unlucky doesn't faze Ozuna.
"I don't worry about that," he said. "If you worry about that, you get in trouble in your mind."
Ozuna likes to keep things loose and not put any unnecessary pressure on himself.
"I'm going to stay with 13 now, and let's see what happens," Ozuna said.
Ozuna is expected to be a big part of the everyday lineup. He says he's starting to get into a groove at the plate.
"I'm feeling comfortable," the center fielder said. "I'm getting better every day."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter