The 27-year-old will fulfil his long-awaited dream of playing overseas after coming to terms with the veteran Greek side, who are mired in ninth place at the half-season break
The half-year loan will see the 27-year-old test his mettle overseas for the first time after spending the entirety of his youth and senior career with the capital city club. Kajiyama, who also represented Japan at the youth level and in the 2008 Beijing Olympics, scored two goals in 26 appearances this season for 10th-place Tokyo in their return from the second division.
"I've been able to grow as a player in these 17 years thanks to my team-mates, staff, and supporters," said Kajiyama, one of a handful of Tokyo players to have contributed to all of their championships, in a statement released on the club's website. "Now I want to raise my level of play even higher at Panathinaikos, and I hope you'll all be able to enjoy watching it happen."
One of the most successful Greek clubs in history, Panathinaikos struggled in 2012 due to ownership problems exasperated by violence at the 'Derby of the eternal enemies' between them and rivals Olympiacos. After finishing 2nd in the 2011-2012 Greek Super League, they are struggling in ninth place this season with just five wins from 15 matches.
Kajiyama will become just the third player to compete in the Super League following Daigo Kobayashi in 2010 and Daisuke Sakata in 2011. In preparation for his loan, FC Tokyo last week announced the signing of Omiya Ardija midfielder Keigo Higashi.
After the holiday break, Panathinaikos will resume their Super League campaign on Saturday against Levadiakos.