As he looks to stake his claim at Liverpool, Divock Origi claims his loan spell at Wolfsburg has helped mature him as a player.
Stuttgart have signed 31-year-old midfielder Gonzalo Castro from Borussia Dortmund, while striker Daniel Ginczek has left the club.
Wolfsburg have confirmed the signing of Wout Weghorst on a four-year deal from AZ.
Wolfsburg maintained their Bundesliga status with Monday's 1-0 win over Holstein Kiel to seal a 4-1 aggregate triumph.
Olaf Rebbe will take over as Huddersfield Town sporting director on June 1, less than two months after being sacked by Wolfsburg.
Wolfsburg took a significant stride towards retaining Bundesliga status after beating Holstein Kiel 3-1 in the first leg of their play-off.
Victory on the final day was not enough to preserve Bundesliga status for Hamburg, where ugly scenes marred the end of the game.
Bruno Labbadia is the man tasked with guiding Wolfsburg away from the Bundesliga relegation zone.
Wolfsburg's Bundesliga status is once again under threat and they will need their third head coach of the season after Martin Schmidt left.
Bayern Munich's Jupp Heynckes hailed Thomas Muller's impact after Robert Lewandowski's late penalty claimed the points at Wolfsburg.