The 28-year-old has only one year left on his contract and has been linked with several clubs, including Liverpool, Arsenal and Manchester City.
“I have said before how important Gareth is to this club,” Petrov told the Birmingham Mail.
“We should give him time to enjoy things because he had a hard time last summer.
“What he did to come back and make the fans happy again was great.
“There should be no pressure put on him and he will make the decision in his own time.”