The 20-year-old suffered a cruciate ligament injury on the opening day of the season at West Ham United and was expected to be out for eight to nine months.
But Gardner on Wednesday was back training with his Villa team-mates and he could yet return to the first team to help in the fight against relegation.
He said on Twitter: "After seven months of hard work, first day back training today! What a feeling! Hard work pays off! Time to kick on thanks for all your support!"
Paul Lambert's Villa picked up a crucial and dramatic win over fellow strugglers Queens Park Rangers last weekend to move three points clear of the relegation zone.
After the international break, Villa host Liverpool on 31st March, when they will hope to repeat of their 3-1 win at Anfield in December.