The IIHF World Junior Championship takes place Dec. 26 to Jan. 5 in Ufa, Russia.
Matteau, the Devils’ first-round pick at this year’s draft, is coming off a strong November in which he collected eight goals, four assists in 11 games with the Blainville-Boisbriand Armada (QMJHL). The left wing has 14 goals, nine assists in 26 games this season.
Pietila, a fifth-round selection in 2011, has eight goals, two assists in 12 games for the Michigan Tech Huskies (WCHA). The forward posted 10 goals, 14 assists in 39 games as a freshman last season.
Training camp for the U.S. juniors will be held in Tarrytown, N.Y., from Dec. 16-18, with an additional camp set for Helsinki, Finland. The final 23-man roster will be announced on Dec. 23.
The U.S. team is coached by former Devil Phil Housley.