First published: 27th November, 2015, 11:03 AM

By Editor Wayne Veysey | Former Evening Standard, Press Association and Goal chief correspondent with 17 years experience of breaking big stories, including exclusives like this

Follow me on Twitter @footyinsider247

Joe Hart is set to be ruled out of Manchester City’s Premier League clash against Southampton on Saturday with a hamstring strain, Football Insider sources understand.

Manuel Pellegrini is not prepared to gamble on the fitness of his No1 goalkeeper and is ready to turn to his deputy Willy Caballero.

A Manchester City source has told Football Insider that Hart was assessed by City’s medical staff on Thursday and the England international was still suffering from tightness in his right hamstring.

City’s plan is for Caballero to take over in goal for the next two matches. He had been pencilled in for next Tuesday’s League Cup quarter-final against Hull City even before Hart sustained his injury in the Citizens’ 1-0 Champions League defeat at Juventus on Wednesday night.

Hart was substituted after 81 minutes in Turin and replaced by Caballero, who struggled badly in his only other Premier League appearance of the season to date, the 4-1 mauling at Tottenham in September.

Speaking after the Juventus defeat on Wednesday night, Pellegrini said Hart has been suffering from a back problem for the last week and suggested the hamstring injury could be related.

The England goalkeeper has joined a treatment room that already includes Vincent Kompany, David Silva, Wilfried Bony, Eliaquim Mangala and Pablo Zabaleta as well as long-term absentee Samir Nasri, who faces a battle to play again this season.

Double blow: Pellegrini will once again be without key duo Silva and Kompany

Injury blow: Pellegrini says Hart has been suffering from a back problem for the last week

Pellegrini ruled Kompany out for another fortnight but said Silva could return against Southampton at Etihad Stadium on Saturday following a two-month absence with an ankle injury.

Bony could also be recalled to the substitute’s bench after missing three weeks with a hamstring problem.