Manchester City are on the verge of taking their summer spending close to £80m after Lazio accepted a £17m bid for the Serbia international Aleksandar Kolarov today.

Kolarov is an attacking left-back renowned for his powerful shooting and ability from set pieces – his style has seen him being labelled as the Serbian Roberto Carlos – and he has been identified to take over from Wayne Bridge in a new-look defence also featuring Jerome Boateng, the £10.5m recruit from Hamburg.

Bridge has not convinced the City manager, Roberto Mancini, that he is good enough for a team that aspires to challenge for the Premier League title in the coming season and the former England international can expect to start on the bench if the 24-year-old Kolarov agrees to become the club's fourth signing of the summer.

Real Madrid, Juventus and Internazionale have also approached Lazio but City are the only club to have reached an agreement and are hopeful Kolarov, who played in two of Serbia's group games in the World Cup, will not be deterred by the fact that his potential new employer will not be involved in the Champions League. If everything goes according to plan, he should take his medical in the coming days and will link up with the rest of Mancini's squad on their pre-season trip to the United States.

City have also signed David Silva from Valencia and Yaya Touré from Barcelona, both for around £25m, and the club's transfer business since the Abu Dhabi United Group took control 22 months ago is likely to go through the £300m mark in the coming weeks.

James Milner remains a target and City are hoping to reach a compromise with Aston Villa over a fee. An opening offer of £20m was turned down in May and Villa have said they want £30m pounds, but it helps City that Milner is known to want the transfer to go ahead.

Similarly there will be new attempts to resurrect a deal for Wolfsburg's prolific striker Edin Dzeko, despite the huge disparity in the valuation of the player. Wolfsburg are asking for a fee of around £45m whereas City are adamant they will not pay significantly above £30m.

Mancini's players are currently in Portland and Joe Hart has cut short his holiday to join them for the start of their pre-season programme. That begins with a game against Portland Timbers on Saturday and Hart hopes to convince Mancini that he should start the season in goal ahead of Shay Given, even if the Republic of Ireland international has recovered from the shoulder injury he suffered towards the end of last season.

Hart was not originally due to join up with the squad until they go to New York next Thursday but, mindful that this could be a season in which he also establishes himself as England's first-choice goalkeeper, he has changed his plans to try to get a headstart on Given.