Where have you heard such a thing ?

Turkey was strictly neutral and generally was negative to Bulgarian expansionism; both because the Balkan wars were a recent memory and because it did not want any prevailing Balkan force.

The Germans were quick to appease Turkey and maintained control over the area of the Greek-Turkish border in Thrace which was overall handed over to Bulgaria. With the German assurances, Turkey offered no diplomatic opposition, (military was never an option to begin with since Turkey valued its neutrality), to the invasion of Greece by Bulgaria. Bulgaria invaded and occupied brutally Thrace aiming in ethnically cleansing it and directly collaborating with the Germans in the extermination of the thousands-strong Jewish population which was shipped to Auschwitz.

So Bulgaria did invade Greece. Turkey did not threaten action but simply required - and received - diplomatic assurances by Nazi Germany. The reason for their opposition was not the well-being of Greece but Bulgaria posing threat to Turkey itself.

source Στέμμα και Σβάστικα, H.Fleischer