Roberto Firmino has suffered a \"serious\" hamstring injury and is unlikely to return after the international break next week.
Firmino limped off a substitute in Wednesday\'s Champions League match against Atletico Madrid.
\"Losing Bobby Firmino is a blow,\" Klopp told a news conference.\"I don\'t think I need to say how big it is. It\'s a serious injury.
\"We talk about weeks -- more than four I consider as a serious injury. Then we have to see. Bobby is a quick healer.\"