The midfielder is due to sign for TSG on a season-long deal.
Emery said today: "It's a very big chance for him and the level there is important. We think he needs, because he is very young, he needs to take a new level to play, a new level also to take minutes, to take experience and it's for that reason we were speaking at the club with the coaches about this possibility. And also, with him, we decided together: club, coaches and the player.
"It's a good chance for him to take minutes in and play, and then come back with us because I think he is signing a new contract with us.
He added: "I think it's not a possibility for more than one player to leave. Maybe young players there will be possibilities. Only one young player for the same situation with Reiss to take minutes at a big level."