Christian Pulisic will be out several weeks due to a combination of tiredness and picking up a thigh injury in training.

"Before Christmas he did report a bit of tiredness so he came out of the team and I was worried about him picking up an injury. He was in pain when it happened. He's a good player that provides competition in wide areas and can make things happen. He was in good form for a period. He picked up an injury a day before the Forrest game. [An] injury in the abductor, a tendon injury. Nasty injury," said Lampard.

Lampard added that Chelsea are looking to sign a striker in the winter window.

"We created 53 chances in our past three league games and scored no goals. It's going to hurt you in the league. We get into the final third a lot but we are not converting chances. In terms of play, we're controlling big parts of games, but we're not taking our chances. We have to get things right and we work on that in training. We need to find that killer instinct."