Stindl began his career on youthside for TSV Wiesental and joined in summer 2000 to the c-youth from Karlsruher SC. Here started his professional career with Karlsruher SC, making his first appearance on 15 March 2008 in the Bundesliga. He was substituted on in the 81st minute in a 0-1 defeat to Eintracht Frankfurt. On 29 November 2008, Stindl scored his first Bundesliga goal against Hannover 96. In February 2010, he announced his intention to leave Karlsruher. On 16 March 2010, his transfer to Hannover 96 was confirmed.