Gakpo left the pitch at the interval to be replaced by Diogo Jota, having scored on the stroke of half time to equalise.
However, Klopp revealed post-match that the Reds’ No.18 had suffered the injury in a foul shortly before the goal.
“He scored a goal but afterwards, but after that shot he felt it even more. It was from the foul before,” explained Klopp.
On the injury, the boss said it was: “The biggest problem of the game, to be honest… before Cody Gakpo scored, we got a free-kick and he got injured and he is now with a brace limping down the corridor.
“That’s my biggest problem, to be honest, in this moment. We lost two [to red cards] and maybe a third player – really bad, really bad. So, yes, that’s something we have to deal with obviously.”
Asked about the severity of the injury and whether it might be a ‘bad one’, Klopp said: “Possibly, I don’t know.”
After that, there’s an international break, followed by the Merseyside derby on October 21.