His lawyer, Gregory Ioannidis, has vented anger at the Greek management team for bringing Samaras on as a substitute during the World Cup qualifier against Latvia.
The 27-year-old Celtic player helped Greece turn a 0-1 deficit into a 2-1 win, but Ioannidis said Samaras should never have played because of a back injury.
He posted a series of tweets on Twitter during the match:
"Latvia Greece 1 0 at half time and Sammy comes on. Hope he returns healthy for the Champions League given that his back is bad."
"Unfortunately Sammy picks another injury and he is off. I will have a few things to say now. Why did they have to use him?"
"Sammy shouldn't be playing in the first place with his bad back. He is now in terrible pain and his left arm is injured."
"Sammy needs to get back to Glasgow asap. He needs an MRI scan and I fear the injury is extremely serious. Gutted."
One report suggested Samaras could be out for about six weeks. Celtic open their Champions Leage campaign at home to Benfica on September 19, then travel to Spartak Moscow on October 2, before entertaining Barcelona three weeks later.