Adam was enjoying an encouraging partnership in midfield with Lucas and the pair have also gelled well off the pitch.
"We are all really sad for Lucas because he's been one of the best players for us again this season," Adam told Liverpoolfc.tv.
"He's gutted and he knew when he got the injury it didn't feel right, but we are all behind him and giving him support. He's a terrific player and it's a big blow for us.
"We have been playing well together but he is a top Brazilian international and has been fantastic for us.
"He has had a lot plaudits for the whole season but Luis Suarez has stolen the limelight because he has been terrific, but Lucas deservedly got man of the match against Manchester City.
"He is going to be a loss but I texted him the other day and told him he will come back stronger mentally, and physically a better player.
"It will be a hard time for him but we will all get him through it, all the players and staff. He will be back for us next season."