The Borussia Dortmund centre-back pulled up shortly before half-time in Greece's uninspiring 0-0 draw with Portugal in Oeiras on Saturday with what appeared to be a hamstring problem.
Initially there were fears that Papastathopoulos' participation in the upcoming FIFA World Cup could be in doubt, but reports in the Greek media suggest that the damage is not as bad as first feared.
While Tuesday's fixture against Nigeria in Pennsylvania is likely to come too soon, coach Fernando Santos could welcome Papastathopoulos back into the squad for the final warm-up game versus Bolivia at the Red Bull Arena on Friday.
Santos' attention may turn to the other end of the pitch, where Greece showed a notable lack of goal threat against Paulo Bento's men.
But, with neither forward making a strong case, Santos may give opportunities to the likes of PAOK's Dimitris Salpingidis and the experienced Theofanis Gekas of Konyaspor, the duo no doubt keen for action before their World Cup opener with Colombia on June 14.
Coach Stephen Keshi left the likes of goalkeeper Vincent Enyeama and midfielder John Obi Mikel out of squad, as Uche Nwofor's 90th-minute goal rescued a draw at Craven Cottage.
Speaking to The Guardian, he said: "In the past few years my only regret is that, as I've become a better player, I probably would have got more goals for myself and the country but I missed out a bit.
"I've missed a year and a half, missed out on the cup they won, unfortunately. I wish I was part of that squad because I've played in four Africa Nations and got three bronze medals, never a gold.
"But I can't look back. This is another opportunity for me."
