The teenager will join the Bundesliga club in 2017.
Everton were beaten 3-1 by Manchester City at the Etihad Stadium last night.
Toumani Diagouraga only moved to Leeds United from Brentford last week.
The 23-year-old joined the Championship side shortly after Austin departed for Southampton.
Chris Dawson has joined Rotherham United on a free transfer.
Tottenham Hotspur are genuine title contenders in the Premier League.
Everton surrendered a good position in their League Cup semi-final against Manchester City, as they were knocked out of the competition at the Etihad Stadium.
Brad Walker is currently on trial at Wolverhampton Wanderers from Hartlepool United.
Mark Hughes is hoping to tie the Spaniard down to a longer deal in an attempt to stave off interest from their Premier League rivals.
Here is how we predict West Ham United will line up against Liverpool this weekend: