The Brazil international was forced off with a dead leg just 13 minutes into Monday's win at Watford.
"The injury is much better. It was a hard tackle and what happened was a dead leg. It caused a lot of pain in the area I was hit, but the pain has reduced now," Coutinho told liverpoolfc.com.
"At the moment, I am feeling very well – the first couple of days were the most painful.
"Of course, when you have to come out of such an important game like this one, and when you leave that early, it frustrates you, but thanks to God it was nothing major – just a strong tackle.
"It was nothing too serious and the main thing was we won the game and we left the match very pleased and happy because the result was very good for us.
"The main thing was for us to come home with the three points."