Petrov was officially unveiled as a Bolton player today following his release by City at the end of a three-year deal.

The Bulgaria international, who was brought to Eastlands by Sven-Goran Eriksson in 2007, had hoped to extend his time there despite struggling to hold down a place in the team over the last two seasons.

Persistent knee problems and a constant stream of expensive new signings arriving at City made life tough for Petrov - but the midfielder says he was most frustrated by the club's lack of communication with him about his future.

"It was frustrating, but not because I didn't play - I understand, because they are buying big stars now for so much money," Petrov said.

"Every time I played on the pitch I showed that I have a place in this team, but okay, the decision is the manager's.

"But the worst thing is that the communication in this club with the players who do not play is not professional.

"I am 31 years old and I felt like I was 13 there. Nobody spoke with me about my situation - they knew that my contract was finishing."

Despite his disappointment at how his spell with City finished, Petrov was keen to thank the medical staff there who helped him overcome his knee injury - which forced him to miss the end of the 2009-10 campaign - in time to start pre-season training with his new club.

"The physio and doctors there tried to do their best for me and I want to say thank you," said Petrov.

"They helped me with my recovery so I could start pre-season at whichever club. I want to say thank you because that was very professional."

Petrov will undertake a specialist training programme with Wanderers to ensure he stays in peak condition, and he admits he also feels stronger in mind after coming through one of the most difficult periods of his career.

"When we played with (former City boss) Mark Hughes and they gave me the chance, I scored goals and the next game I was on the bench," Petrov said.

"But I am a professional player, I know that that can happen.

"It was for the first time in my career that I was a player who did not play non-stop, but that can make me stronger now.

"I am stronger and I know that it is very bad news in football when you are injured, because you can do nothing.

"I am sure if I stay without injury, I can help Bolton to play good football."

Given his recent fitness record, Petrov could be regarded as something of a gamble on Bolton's part and he is determined to repay the faith shown in him by Wanderers boss Owen Coyle.

"It was a very hard decision maybe for Bolton, so I am very happy that they have given me a chance," said Petrov.

"I want to show now that they haven't made the wrong decision."

While Petrov has been finalising his move, City have been as active as ever in the transfer market, acquiring Spain midfielder David Silva this week for a fee believed to be in the region of £25million.

With Barcelona's Yaya Toure also reported to be on his way to Eastlands, City seem to have their sights firmly set on a challenge for the Barclays Premier League title next year - but Petrov has warned that unless they play as a team, they will achieve nothing.

Asked if he thought City could win the league next season, Petrov said: "If you see the players they have bought in the last few days, everybody is saying yes.

"But everyone expected that Italy and France would go ahead (in the World Cup) and after three games they went home.

"At this moment in football it is not how much you spend on players; what is most important is what you have on the pitch - a team, or no team.

"You can pay £100million, £200million for one player but if the players do not play with the team - for the team first, and for themselves after that - you can do nothing."

Petrov took part in his first training session with his new team-mates this morning, along with striker Robbie Blake, who has also arrived on a free transfer after leaving Burnley.