|Full name||Athanasios Petsos|
|Date of birth||5 June 1991|
|Place of birth||Düsseldorf, Germany|
|Height||1.84 m (6 ft 0 in)|
|Playing position||Defensive midfielder|
|1999–2001||Düsseldorf 99 SC|
|2010||Bayer Leverkusen II||8||(0)|
|2010–2012||→ 1. FC Kaiserslautern (loan)||39||(0)|
* Senior club appearances and goals counted for the domestic league only and correct as of 1 August 2015.
Petsos started his football career at the age of eight for Düsseldorf 99 SC. In 2001 he was lured away to professional club Bayer Leverkusen. He progressed through the youth system and was part of the team that finished runner-up in the Under-19 Bundesliga in 2010. He made his debut for the reserve team in March 2010. He made seven more appearances in the 2009–10 season while continuing to play for the under-19 team. He made his Bundesliga debut on 24 April 2010 against Hannover 96.
In 2010, Petsos signed his first professional contract agreeing to a four-year deal and was immediately loaned out to 1. FC Kaiserslautern for two seasons. He made his full Bundesliga debut for the club on 13 November 2010 against VfB Stuttgart. He made a total of 42 appearances for the club.
In 2012, Petsos signed for newly promoted SpVgg Greuther Fürth on a three-year deal. He made his debut for the club on 18 August 2012 in a DFB-Pokal match against Kickers Offenbach, he then went on to make his Bundesliga debut on 31 August 2012 against Mainz 05. He went on to make a total of 15 appearances for the club.
On 15 July 2013, Petsos joined Austrian club Rapid Wien on a three-year deal.  The Rapid Wien Football Director Helmut Schulte on the transfer of a player who spent most of his formative years with Bayer Leverkusen said: "I'm very happy that it was possible for us to remain active in the transfer market and bring in a defensive midfielder, who, despite his age, already has a wealth of experience. Thanks to the streamlining activities going on throughout the club its been possible to remain in the hunt for new talent and I'm extremely grateful to club President Rudolf Edlinger amongst others for the work that has gone into making it possible for us to realise this transfer.” He made his debut for the club on 27 July 2013 against Wiener Neustadt. On April 2015, the 23-year-old Greek midfielder has been linked with Olympiakos in the past and according to reports the Greek giants have revived their interest in his services. Petsos, whose contract at the Austrian club expires in 2016, has become a regular member of Rapid Wien for yet another season and Olympiakos could consider a move for him in the next transfer window. 
- "Στην Γκρόιτερ Φιρτ ο Πέτσος". xrimaonline.gr. 23 May 2012.
- . Rapid sign Petsos Retrieved 15 July 2013.
- . New signing: Welcome to Hütteldorf Thanos Petsos Retrieved 18 July 2013.
- Rapid lässt Wiener Neustadt keine Chance. sportnet.at. Retrieved 14 August 2013.
- "Petsos linked with Olympiakos". 5 April 2015.
- . bleacherreport.com. Retrieved 3 May 2015.
- "Τρομερό γκολ ο Πέτσος (vid)". 3 May 2015.
- Athanasios Petsos at National-Football-Teams.com
- Thanos Petsos at fussballdaten.de (German)
- Thanos Petsos – UEFA competition record
- ESPN FC profile