Early career Kroos began his career in 1997 at
Greifswalder SC and was in summer 2002 scouted by
Hansa Rostock. Kroos played for Hansa Rostock II for two seasons. Kroos made his professional debut in a third round
German Cup match for Hansa Rostock against
VfL Wolfsburg on 28 January 2009. He was substituted on in the 69th minute for
Sebastian Svärd. Two days prior to the relegation of Hansa Rostock, Kroos announced his departure from the club.
Werder Bremen Kroos signed a three-year contract for
Werder Bremen on 15 June 2010. He finished the
2010–11 season with six matches played. He finished the
2013–14 season with a goal in 20 matches played. He finished the
2014–15 season with 29 matches played. During the
2015–16 season, Kroos made nine appearances before moving to Union Berlin. He joined the club permanently in June, reportedly for a transfer fee of €500,000 and a 20% share of a potential future transfer fee. He finished the
2015–16 season with two goals in 12 matches played for Union Berlin. He finished the
2016–17 season with two goals in 31 matches played. He finished the
2017–18 season with a goal in 30 matches played.
Eintracht Braunschweig In September 2020, after his contract with Union Berlin expired, Kroos moved to
2. Bundesliga side
Eintracht Braunschweig on a two-year contract. He retired from playing in July 2021. ==International career==