Liverpool forward Roberto Firmino faces spell out with serious hamstring injury

Liverpool's Brazilian forward Roberto Firmino sustained a serious hamstring injury in Wednesday's 2-0 Champions League win over Atletico Madrid and there is no timeline for the 30-year-old's return, manager Juergen Klopp said on Friday.

The injury could rule Firmino out for a number of matches, starting with Sunday's Premier League trip to West Ham United as second-placed Liverpool look to close a three-point gap on leaders Chelsea.

Firmino has made eight league appearances this season and has scored four goals. He has another two goals in the Champions League from three games.

"Bobby is not good news with a serious hamstring injury, really unfortunate. We don't know exactly how long he'll be out but it'll be not now after the international break directly. We have to work on that," Klopp told Liverpool's website.

Klopp said defender Joe Gomez (calf) and midfielder Curtis Jones (eye) will also miss Sunday's clash due to injuries.

"Curtis is a completely different story (to Firmino), he was unlucky in training – he got a finger that scratched the eye. I had a lot of injuries to players in my career, that was not involved," Klopp added.

"He is on the way back but we have to see how long exactly. He will be back after the international break, for sure, but in the international break we have to see when he can start doing proper stuff again.

"And Joey, hopefully after the international break as well."