The 36-year-old was applauded during the 19th minute of every match, in keeping with his former shirt number, as he received treatment for the condition.
He will now travel with the squad to Austria after training with the Under-21s earlier in the year.
Villa manager Roberto di Matteo made the decision to welcome the Bulgarian back into the fold – three years after he made his last competitive appearance in 2013.
Petrov turns 37 next month and has been in training at least three times a day to get back into peak physical condition.
During his seven years at Villa Park, the former Celtic midfielder made 186 appearances for the Midlanders, scoring nine goals. Re-joining Villa on a permanent basis remains a possibility if he can prove his fitness.
A statement said: “Aston Villa Football Club is pleased to confirm Stiliyan Petrov will take part in pre-season training at first-team level. Manager Roberto Di Matteo has revealed the former Club captain will travel with the group to Austria as he joins the squad at their training camp.
“Stan will report next week with the rest of the group.”
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