Cologne - While the Bundesliga's many stars continue to build up their fitness levels ahead of the new season, clubs up and down the country are working tirelessly behind the scenes to strengthen their playing staff in time for the big kick-off in mid August.

Over the next few weeks, bundesliga.com will be taking a closer look at each of the 18 top-flight clubs’ summer transfer dealings so far. Next up in the series: VfB Stuttgart…

How they fared in 2014/15

Only a 2-1 victory over SC Paderborn 07 on the final day was enough to keep Stuttgart in the Bundesliga safe house for another season. Until then, they had spent just eight Matchdays above the relegation zone, while 16 of the 34 were spent rooted to the foot of the standings. Much like in 2013/14, it took relegation saviour Huub Stevens’ midas touch to lift them out of the mire.

© gettyimages / Grimm

Ins

Mitchell Langerak (Borussia Dortmund)

  • Left his native Australia for Bundesliga side Borussia Dortmund in 2010
  • Saved a Mario Götze penalty as BVB overcame holders FC Bayern to reach the final of the 2015 DFB Cup

What he offers: An accomplished all-round game as well as UEFA Champions League experience

Przemyslaw Tyton (PSV Eindhoven)

  • A 13-time Polish international goalkeeper
  • Has already played in the Spanish and Dutch top flight

What he offers: A level head with good shot-stopping abilities

Emiliano Insua (Club Atletico de Madrid)

  • A well-travelled left-back capped four times by Argentina
  • A 2007 FIFA Under-20 World Cup champion

What he offers: A willingness to get forward and put crosses into the box

Jan Kliment (FC Vysocina Jihlava)

  • 21-year-old striker, who can also play in midfield
  • Finished top scorer at the 2015 UEFA Under-21 European championships with three goals

What he offers: Clever movement in the final third and an end product

Lukas Rupp (SC Paderborn 07)

  • 24-year-old attacking midfielder
  • Scored four goals in 32 outings for relegated Paderborn in 2014/15

What he offers: Good reading of the game; not frightened to drive forward

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Outs

Sven Ulreich (FC Bayern München)

  • Ambitious goalkeeper, who will play understudy to Manuel Neuer at Bayern
  • Made his professional debut for Stuttgart, having joined the team’s youth setup in 2007

Gotoku Sakai (Hamburger SV)

  • Japanese international full-back capable of playing on either flank
  • Made 87 Bundesliga appearances in a Stuttgart shirt

Joshua Kimmich (FC Bayern München)

  • Composed central midfielder and youth international (20)
  • Spent the last two seasons on loan at Bundesliga 2 club RB Leipzig

To-do list…

Stuttgart have brought in a useful blend of young and experienced heads so far. Most of new head coach Alexander Zorniger's summer acquistions have the quality to go straight into the first team, but it wouldn't be a surprise to see the club trying to wrap up deals for one or two more defensive reinforcements before the window shuts - especially given Antonio Rüdiger's ongoing injury problems.

Editor’s note: Not all summer transfers will be discussed here. The players featured in this article made at least ten league appearances for their respective clubs last season, chipped in with numerous goals and assists or made other significant contributions to their team. For an overview of the 2015/16 summer transfers, click here.