Young missed last weekend's goalless draw with Chelsea after suffering the setback in training the previous day.
But scans have revealed the injury is worse than first feared and Villa boss Gerard Houllier is resigned to being without the former England full-back for at least a fortnight.
That means Young is likely to miss Saturday's clash at Sunderland, the Carling Cup meeting with Burnley on Wednesday and the home derby with Birmingham on October 31.
Houllier confirmed: "The doctor has told me Luke will need at least another two weeks (to recover) because it is a minor tear.
"It's a blow because it's worse than we initially thought."
Striker Gabriel Agbonlahor is still unavailable after undergoing minor groin surgery.
But fellow striker Emile Heskey, winger Marc Albrighton and defender Richard Dunne look like winning their battle to be fit.
Heskey and Albrighton were ruled out of the Chelsea clash through a back injury and sickness respectively.
Dunne had to be substituted after only 12 minutes with an ankle problem.
Houllier said: "Richard has trained normally. Marc returned to training on Monday. Emile is much better. He trained normally.
"As for Gabby, I hope at some stage next week he may be able to train. He won't be involved this weekend."