Career
He can play point guard or shooting guard. Mantzaris began his professional career in the Greek A2 League with Peristeri. On September 5, 2011, Mantzaris signed a four-year deal with the Greek League club Olympiacos Piraeus.
In January 2013, Mantzaris suffered a season-ending knee injury, after rupturing the anterior cruciate ligament in his right knee.
On 29 July 2014, Mantzaris extended his contract with Olympiacos through 2017. 2008 Albert Schweitzer Tournament: 01 ! Pro career.