The Brazil forward lasted just 33 minutes as a half-time substitute in the midweek Champions League win over Atletico Madrid before he was forced off.
“Bobby is not good news with a serious hamstring injury, really unfortunate,” Klopp told liverpoolfc.com.
“We don’t know exactly how long he will be out but it will be not now after the international break directly. We have to work on that.”
“Curtis is a completely different story; he was very unlucky in training – he got a finger that scratched the eye,” added Klopp.
“I had a lot of injuries to players in my career, that was not involved. 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.”
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in