The Bulgarian has been a key performer for Villa this season and has only 17 months remaining of the four-year deal he signed following his £6million move from Celtic in the summer of 2006.
But Petrov insists his own contract is on the back-burner while Villa battle for a Champions League spot and UEFA Cup glory.
And he concedes Barry's own plans - he came close to moving to Liverpool last summer - will have a significant bearing on what lies ahead for him in the long term.
The England player's contract also expires in the summer of 2010, and Petrov said: "The manager will try to show everybody that he wants to build something big here and one of the things is to keep Gareth Barry because he is maybe the most important player at the club.
"If we keep Gareth it will also send out a message to all of the players, a big message that we are in for something big here next year.
"We all hope he is going to stay because he is one of the best midfielders in the country and you try your best to keep him if you want to achieve something."
Petrov is content to focus for the time being on helping Villa's pursuit of success and they host CSKA Moscow in the first leg of a UEFA Cup clash on Wednesday with a place in the last 16 at stake.
On the subject of his contract, he said: "There have been no talks - not at all. My job now is to play football.
"If the club is interested to offer me a new contract, they will contact my agent and speak about that.
"It is no priority at the moment. There are other priorities at the moment - for the club to finish in the top four of the Premier League and go as far as we can in the UEFA Cup.
"That is the most important thing."
Petrov dispels the theory that Villa have an advantage as CSKA have not played a competitive game since December 4 because of the winter break in Russia.
But he acknowledges it is a crucial 72 hours for the club with Villa hosting Chelsea in a meeting of third versus fourth in the Premier League on Saturday.
Villa will be looking to bounce back after crashing out of the FA Cup 3-1 at Everton on Sunday.
He said: "We were really disappointed with the way we played against Everton. We were on the back foot and not as sharp as we normally are. They deserved to win.
"It is a very big week for us with two more very important games coming up. People might think it is easy against CSKA because their season hasn't started yet.
"But we already know about them from looking at DVDs and they look a very strong team with pace and players who can hurt you.
"They will have been aware when the draw was made of how good we are and we also have players who can hurt them. They will want to stay in this competition and will be ready for this game."
Barry will return after being ruled out of the defeat at Goodison Park through suspension but fellow midfielder Steve Sidwell is banned for his sending-off against Hamburg in December.