"I've had to marinate on that for a while," Duffy said. "It's a huge honor. It's an incredible feeling to wear USA on your chest. It's a big deal. I'm taking pride in that. I can't wait."
Duffy is scheduled to pitch March 12 against Canada.
"I just got word I'll pitch in the following rounds, too, due to a couple of injuries on the team," Duffy said.
The World Baseball Classic runs from Monday through March 22. In the U.S., games will air live exclusively in English on MLB Network and on an authenticated basis via MLBNetwork.