Walchak is the third player to enter the portal from Penn State since the Blue-White Game.
Head coach Rob Cooper was ejected from the competitive, back-and-forth game.
Janecke registered three goals for Team USA en route to the squad's world championship.
"Whether they are here with us today or from far away, we all have a connection to one symbol that makes our love for Penn State grow."
The Texas native's five-catch, 80-yard showing helped elevate the Nittany Lions' offense during his Blue-White outing.
Brewer is the ninth commit to join Penn State's Class of 2024.