Fabian Delph is set to miss Manchester City's first two games of the season, manager Manuel Pellegrini has revealed.
The £8 million summer signing was carried off with a hamstring injury just 18 minutes into his first appearance for the club - a pre-season friendly against Real Madrid - just over a fortnight ago.
The England midfielder has now been ruled out of Monday's Barclays Premier League opener at West Brom and the following week's clash with Chelsea. A competitive debut against Everton on August 23 might also be unlikely.
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Pellegrini said: "I think he needs 15 days more. That will be a month from the injury he got in pre-season.
"He played just 17 minutes but you saw in those 17 minutes that he will be an important player for this club."
Delph joined City from Aston Villa after a remarkable change of heart last month, just days after publicly rejecting a switch to the Etihad Stadium.
His City career is beginning just as striker Edin Dzeko's appears to be coming to an end.
The Bosnia international, bought for £27 million four years ago, is in the process of joining Roma and has been pictured in the Italian capital receiving the acclaim of fans.
Pellegrini said: "Edin made a big contribution to this club. He won two titles here and was a very good player.
"But I think teams need every year to change some players and he has been here more than four years. That was enough for him, he needs a change.
"I appreciate what Edin did for the team and also for me because we won two trophies together.
"He will be a very good player for Roma and he will have a successful season. I send him the best wishes."
Dzeko scored 72 goals in 187 appearances for City.
City playmaker David Silva tweeted: