Manchester City have confirmed captain Vincent Kompany suffered a groin injury at Swansea City in midweek, with no date set for the Belgian's return.
Kompany limped off in the closing stages of the 2-1 EFL Cup win in Wales, his first appearance in four months after sustaining a similar problem in the Champions League semi-final against Real Madrid on May 4.
His 2015-16 season was disrupted by a nagging calf injury that restricted him to just 25 appearances for club and country.
The latest setback is another blow for Kompany, who has suffered 33 injuries since moving to England from Hamburg in 2008.
The 30-year-old has remained with the squad in Wales ahead of City's Premier League clash with Swansea, but is not being considered for the clash at the Liberty Stadium.
Two of John Stones, Nicolas Otamendi and Aleksandar Kolarov are set to line-up at the centre of Pep Guardiola's defence.