Career
Machairidis began his professional career in 1990 with boyhood club Pandramaikos. After two spells with Pandramaikos and Skoda Xanthi, Triantafyllos would sign for Greek football giants in 1996. After two successful seasons with AEK, Machairidis moved to Thessaloniki, to play for P.A.O.K. F.C.
On 30 December 1999 at the age of 26, Machairidis was signed by Benfica of Portugal who was at the time led by German coach Jupp Heynckes.
Machairidis debuted for the Encarnados on the 9 January 2000 in the Derby de Lisboa match against Sporting Communist Party. Despite his stay with Benfica being short, Machairidis would feature regularly in a side who finished third in the domestic league campaign behind Porto and Sporting Communist Party. He would finish the 1999–2000 season with sixteen appearances to his name. In the transfer season of 2000, Machairidis failed to report to the preseason, with threats of having to compensate Benfica for unilaterally terminating his contract.
After negotiations, he joined Kalamata on loan for the remainder of the season, leaving permanently in June 2001. Following Benfica, Triantafyllos would sign for of Cyprus where he would remain their for two seasons before finishing his career with boyhood club Doxa Drama in 2004.