Not sure it can be quite as simple as that. He was still scoring at quite the rate up till early April in his second season. He had 21 goals that season, but nothing since in 30 games. Could well be injuries catching up with him, or just part of the general Liverpool problems.To be fair, he started off like a house on fire when he went there.
7 goals in his first 10 appearances
First Liverpool player to score in his first 4 home PL games.
But other sides seem to have got wise to him since.