Manchester City are waiting to discover for how long their captain Vincent Kompany will be sidelined.
Kompany is expected to undergo a scan on his groin after coming off injured at half-time in Sunday's 4-2 defeat to Manchester United.
The Belgium international had first felt the problem in the previous week's 2-1 loss at Crystal Palace.
But although he was able to complete that game, Kompany could not train properly for much of last week and City will find out if the injury-prone 29-year-old will be absent for much of the remainder of their season.
Manager Manuel Pellegrini said in his news conference at Old Trafford: "Vincent didn't work the whole week with normality, he just the last two days. He just has a problem with his groin. He said at half-time he couldn't continue."
Eliaqium Mangala came on for Kompany against United and the £40 million defender would be the likely replacement if he were ruled out.
Kompany has spent two previous spells on the sidelines already this season with hamstring injuries and also has a history of groin and calf problems.
City have six league games remaining, beginning with a home clash against West Ham on Sunday, and a four-point lead over fifth-placed Liverpool as they look to secure a fifth successive season of Champions League football.