Manchester City defender Micah Richards is set to spend another month on the sideline with an ankle injury.
Richards suffered the problem on Olympic Games duty and manager
However, the 24-year-old's recovery has not gone quite as well as planned.
"I think it will be three or four more weeks," said Mancini.
Meanwhile, Arsenal will assess Theo Walcott ahead of its season opener against Sunderland.
Midfielder Alex Oxlade-Chamberlain and defender Laurent Koscielny will both miss out having withdrawn from the midweek internationals.
Off-season signing Santi Cazorla will be monitored after his trip to Puerto Rico with Spain, while Lukas Podolski is expected to lead the attack following the sale of Robin van Persie to Manchester United.
Midfielder Jack Wilshere continues his rehabilitation from an ankle injury as does defender Bacary Sagna.
West Bromwich Albion manager Steve Clarke could be left counting the cost of the midweek international friendlies ahead of his side's opening match against Liverpool.
Scotland's James Morrison and Sweden defender Jonas Olsson both returned from playing for their countries with slight injuries and are being assessed ahead of the weekend's match.
New signing Markus Rosenberg is unlikely to be fit in time while midfielder Graeme Dorrans remains on leave with his daughter in hospital due to meningitis. Striker Shane Long is available despite missing the Republic of Ireland's match with Serbia.
New signing Wigan Athletic signing Ivan Ramis is the side's leading fitness doubt ahead of its first round match with Chelsea.
The Spain international, a $6 million arrival from Real Mallorca, has a hamstring strain and heads two concerns for manager Roberto Martinez, with the other being James McCarthy.
Striker Victor Moses is in the squad despite interest from Chelsea, while Fraser Fyvie, Arouna Kone and Ryo Miyaichi are all in line to make their debut.
Meanwhile, Reading is set to decide whether to include Jem Karacan in its squad when it returns to the English Premier League.
Manager Brian McDermott revealed Karacan was "desperate" to put the seal on his return from a broken leg against Stoke City.
But the Championship winner will be without Jimmy Kebe and Jason Roberts, who serves a two-match ban.
English Premier League
Chelsea striker Demba Ba would relish more competition with Fernando Torres next season - but is also keen to partner the Spaniard.