Ammann followed up injured teammate Evan Finney as Defensive Player of the Week after getting two wins from two starts over the weekend.
The Canada native was playing in Costa Rica on Saturday and traveled all day Sunday to be back to score Penn State's overtime game-winning goal against Oakland.
Penn State conceded a late goal, but Aymar Sigue buried a chance just two minutes into overtime to give Penn State its second straight win.
Frannie Crouse scored twice as Penn State took down Long Beach State and avoided a third-straight loss.
Penn State opened its season at Jeffrey Field with a win thanks to a Connor Maloney goal.
Shawn Morelli and incoming freshman Emily Frederick will compete at the 2016 Rio Paralympics in cycling and shot put, respectively.