Frank Thomas believes Jose Abreu should be participating in Monday night's Home Run Derby.

Abreu, who leads all rookies in home runs, told reporters numerous times leading up to the event that he didn't want to participate in the event because he feared it would alter his hitting mechanics.

"I'm disappointed," Thomas said. "He's a breakout star. He needs to let the world know who Jose Abreu is."

Thomas, who will be enshrined in the Baseball Hall of Fame this month, will be at the Home Run Derby for a promotional appearance with Gillette, the title sponsor of the event.