Japanese right-hander Yoshihisa Hirano said Monday he is grateful for the opportunity to restart his baseball career with a new team in his mid-30s and looks forward to the challenge that awaits him in the major leagues.

Hirano agreed to a two-year, $6 million deal with the Arizona Diamondbacks in December after 12 seasons with Nippon Professional Baseball's Orix Buffaloes, including the 2008 season he missed due to elbow surgery.

In a news conference in which he introduced himself in English, the veteran reliever said he hopes to prove wrong any doubters who say he is past his prime.

"Given this chance at this age is like starting all over again. I'm really excited and I'm ready for the challenge," he said.

"I'm not worried about my age or about my performance declining. I believe it's still possible for me to improve," he said.

Hirano said he feels the Diamondbacks are young and strong, and are in a good position to aim for a World Series title -- what would be the National League club's first since 2001.

"I'm honored to become a member of the Diamondbacks," Hirano said after trying on his No. 66 jersey. "I want to do my best from Day 1 of spring training (on Wednesday) and hope to help the team become world champions."

Hirano went 48-69 with a 3.10 ERA in 549 games with Orix, where he recorded 156 saves.