Liverpool defender Virgil van Dijk was removed from Saturday's game against Southampton with an apparent rib injury.
With the Reds up 3-0, the Dutch centre-back was involved in a challenge with Shane Long in the 51st minute, and came away holding his side.
Van Dijk was unable to continue and had to be subbed out four minutes later, with Joe Gomez coming on in his place.
The injury will be a worry for the Reds as they begin a difficult run of fixtures.
Liverpool face Chelsea twice in four days next week: Wednesday in a Carabao Cup match and then Saturday in Premier League action.