After a few good seasons, he signed with CSKA Sofia and after two successful games against Servette in the UEFA Cup, the Swiss side bought the 19-year-old for 1.2 million German marks.

He made his competitive debut on 14 July 2001 in a 4–3 home win over Dinamo Minsk in the Intertoto Cup, scoring a goal and laying on an assist.

[2] Petrov made his league debut for Wolfsburg on the opening day of the 2001–02 Bundesliga season, in a 2–1 away loss against Bayer 04 Leverkusen on 28 July.

[4] On 14 October 2006, Petrov suffered an anterior cruciate ligament injury during a game against Recreativo de Huelva and was sidelined for more than six months.

On 24 July 2007, after constant press speculation about him leaving the club, it was reported that Atlético Madrid had placed a £6.2 million price on the player.

Later that day, he left the Atlético Madrid training camp to think over his future with Tottenham Hotspur and Manchester City reputedly interested in the player.

On 25 July, reports in the Spanish press suggested that Petrov had already agreed terms and had medical tests with Manchester City and that only minor details needed completing before finalising a move to Eastlands.

[6] His first Premier League game was on 11 August 2007 when he started in Manchester City's 2–0 win over West Ham United at Upton Park.

[7] After the sacking of Mark Hughes and arrival of Roberto Mancini, he started both league games and scored in the 2–0 win over Stoke City on 26 December.

[citation needed] On 18 April 2010, Petrov announced that his season was over and that he would miss the four remaining Premier League games due to a knee injury.

[15] On 31 October 2013, Petrov made his return debut for the "armymen" after coming on as a second-half substitute in the 1–0 home win over Beroe in an A Group match.