Manchester City lost both of their centre-backs to apparent injuries in the early stages of Tuesday's Champions League last-16 second leg against Dynamo Kiev.
Both captain Vincent Kompany and Nicolas Otamendi left the game in the first half, leaving City to defend their 3-1 advantage from the first leg with Eliaquim Mangala and Martin Demichelis in their place.
The teams were just settling into the game when Kompany, making only his 18th start in all competitions this season, pulled up after turning with the ball to guard it from Oleg Gusev in the fifth minute.
The Belgium international tapped the ball out of play before falling to the floor with a face of utter frustration and will be a doubt for Sunday's Manchester derby as well as Belgium's friendlies during the upcoming international break.
Otamendi then picked up a knock, and though he attempted to play on, Manuel Pellegrini was eventually forced to replace him with Demichelis on 24 minutes.