The midfielder secured his temporary switch from the Emirates on the last day of the transfer window and will stay with his former club until July.
The Russia international conceded he was out of favour under Arsene Wenger and has targeted more playing time in his home nation.
Ashavin told Sport-Express: “When they made an official offer I thought hard about it and realised it would be the right move.
“Coming back to my home team and city would be beneficial to both sides. I haven’t been playing regularly for the Gunners lately and it didn’t seem like things would change soon, so the offer came at the right time and place.
“I think that at the moment a loan is more important to me than to the clubs. I hope to play more football in St. Petersburg.
“You have to earn your right for a first-team spot. Hopefully I can prove my worth to our head coach.”