Possible Clues:

• Diamond-dominating Dominican
• 600-homer club member
• National League's MVP of 1998
• Sports Illustrated 1998 co-Sportsman of the Year
• McGwire contemporary
• He hit his 600th homer 6/20/2007
• Sammy with over 600 homers
• Slugger with 588 lifetime homers
• Member of the 500 home run club
• Chicago slugger