The more punches Adrian Gonzalez throws, the louder the former boxing champion's voice becomes.

"I don't feel 230! I don't feel 230!" Chris Byrd shouts, his arms wrapped around a heavy bag.

Gonzalez, the Dodgers' 230-pound first baseman, continues punching. Byrd continues barking.

"Drive the right hand through!" Byrd orders. "Let's go! Ten seconds!"

To prepare for spring training and the upcoming baseball season, Gonzalez turned the garage in his 11,000-square-foot home into a makeshift boxing gym. Byrd, 42, a retired fighter who twice won versions of the world heavyweight title, comes to visit once a week.

The workouts revealed something about Gonzalez that surprised Byrd.

"That's a world-class athlete," Byrd says.

By his own admission, the four-time All-Star doesn't look like one. Gonzalez is one of the slowest runners on the Dodgers. And his body isn't sculpted like, say, Matt Kemp's. If anything, it's on the soft side.

"You don't work that hard," Byrd recalls thinking before he started training Gonzalez. "All you do is hit a ball."

In the last three months, Byrd learned why Gonzalez has been able to consistently hit for power while earning the reputation as a top defender at first base the last seven seasons.