Ken Rosenthal of FOXSports says that the Oakland Athletics have been the “most aggressive” in terms of contract for free agent Lance Berkman. He adds that the Chicago Cubs and according to a Major League source, the Colorado Rockies have shown interest too.

The first time free agent says he would prefer to return to the National League. He isn’t ready to give up the field yet and become a full-time designated hitter.

“I’m certainly talking to them,” Berkman says of the A’s. “But that’s a situation where they’ve got a very good young first baseman defensively (Daric Barton), and a glut of outfielders.”

“I think they’re looking for a DH. I’m not ready to be a full-time DH. I’m not ruling them out. But I’m not jumping up and down excited about going out and DHing.”

Berkman says that he would like to continue his career on a contending team. In 2010, Berkman started the season with the Astros, but was traded to the New York Yankees mid-year. He made $14.5 million in the final year of his six-year contract.