The former Bulgaria international, who moved to Villa Park in 2006 before retiring earlier this year, believes the 23-year-old has played an important but under appreciated role
Westwood has started 13 of Villa's 15 Premier League games so far in his second Premier League season following a move from Crewe Alexandra last summer.
And former Villa midfielder Petrov believes the 23-year-old's performances have slipped under the radar and has praised the manner in which he has shielded the defence.
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"Some people watching him in his position don't see what he's doing. He gives the security to the team. He does the hard work. He does the dirty work. He is there for the team.
"Sometimes fans don't see that. But, I tell you what, your mates appreciate it. They know what you have done.
"Some supporters look to who crosses it, who scores, who saves a goal. People can forget about his role.
"He is always there. When the other team breaks, he is there. He makes sure the defence is protected. He works his socks off to help his mates.
"Villa must be happy with what he is doing, how he plays and what he does for the team.
"I remember when [former Villa boss] Martin O'Neill starting playing me in that position, that deeper role. Some fans don't see what is happening at the back when you're attacking.
"I was there and I know how hard it is for him. I tell you what, when you go off the field and think 'I was a good team-mate today, I worked hard for them and did everything I could' it makes you feel good."