"At this moment, Mark wants to play so well, he's playing not so well," said the Liverpool boss.
"He's always trying to go forward and he wants to go faster than he has to at this time.
"We don't have any doubt about the quality of the player. He has to work for his place like all the players, but we know he is a top player at a top club and he will do well.
"He has the pace we're looking for. At the moment he's tired because he's training hard, but in few weeks time you will see the quality."