Cabrera, who signed with Kansas City in December, spent the offseason months working out with a trainer in Miami and lost 17 pounds. He's changed his diet and now hits the gym daily.
"I'm healthier than I've ever been. I've lost some weight and I'm working hard," Cabrera, 26, said. "I know I can be the player I was when I started my career."
Last season with Atlanta, Cabrera had a lower batting average (.255), had fewer RBIs (42) and fewer home runs (four) than in the previous season while with the Yankees, the club that originally signed him out of the Dominican Republic in 2001.
"Last year was a bad year for me, but what can you do? It's in the past now," Cabrera said. "I know there is still a lot I can do in my career. Things like last year happen in a career."
Cabrera has experienced success. He hit 36 home runs and racked up 228 RBIs with 250 runs scored in his five seasons starting with the Yankees in 2005. He was eventually traded to the Braves as part of a package for Javier Vazquez before the start of the 2010 season.
The Royals have depth in the outfield. In addition to Cabrera, the list of outfielders includes Jeff Francoeur, Alex Gordon, Mitch Maier, Lorenzo Cain, Gregor Blanco and Jarrod Dyson.
"He and Francoeur have a step lead on everybody else," Royals manager Ned Yost said. "Those guys are veteran guys and have all had success in the big leagues. And probably Alex Gordon, those three guys, probably have a bit of an edge on all of that."