1. FC Union Berlin will have two international representatives during the upcoming international window, which follows Sunday's match in Sandhausen.

Marcel Hartel has been called up to Germany's under-21 squad and Julian Ryerson is named in Norway's side for 2019 European Championship qualification — the tournament will be held in Italy.

Hartel to face Mexico and Ireland:

The 22-year-old attacking midfielder has been a regular featre in the Germany squad over the last 12 months. He has seven appearances to his name and recently took part in Germany's wins over Kosovo and Israel. On Friday September 7, the German U21 side will meet Mexico at the home of Greuther Fürth. The following Tuesday, Germany head to the Republic of Ireland.

Ryerson retains Norway spot:

The 20-year-old, who joined the club from Viking this summer, is likely to make his 11th appearance for the U21 side. Ryerson made his debut in March 2018 for Leif Gunnar Smerud's side against Portugal and has managed to maintain an unbeaten streak of six games. In eight of his 10 previous appearances, he's played for the full 90 minutes.

In October 2017, Hartel and Ryerson faced off in a European Championship qualifier in Drammen with Norway winning 3-1 on the night. On Tuesday, Norway will take on Azerbaijan as they look to improve on their fourth-place position in the qualifying campaign.