The 2002 season started poorly for Lamb, spending the first half of the year with Sandringham. His opportunity came in round 12. One of Melbourne's key defensive players, Alastair Nicholson, had injured his knee in the previous match and Lamb was required to fill in for him. Despite not having a possession, he was selected for the next game. Lamb began to play well, becoming a key figure in the Demons' defence and playing every game for the rest of the season. In round 15, he kicked his first and only AFL goal. In a match late in the 2002 home and away season, Lamb attempted a spoil and landed awkwardly on his neck. He was motionless for several minutes and there were concerns that he may have broken his neck. The incident was described as "sickening", but Lamb only had a slight concussion and he played the following week. He played in both of Melbourne's finals in 2002, was awarded the Demons' "Most Improved Player" award at the end of the year and was described by "The Age" as "the find of Melbourne's 2002 season". Lamb signed a new contract with Melbourne at the end of the season. Despite his form in 2002 and his continued good play for Sandringham, where he was regularly named best on ground, Lamb was unable to gain a consistent position in the seniors in 2003, regularly being overlooked. He played one game, in round 2 against Essendon, but was only on the field for a quarter before being benched for the rest of the game after being beaten by Matthew Lloyd. Midway through the season, after two best on ground performances for the Zebras failed to result in a senior call-up, a rumour of a rift between Lamb and coach, Neale Daniher, began to grow. Daniher dismissed the rumour, saying that the reason Lamb was out of the side was because "he had to lose some weight, improve his endurance and mobility, and learn to play further afield". After he was dropped, he lost four kilograms, improved his up-the-ground play and was regularly one of Sandringham's best players. Although Daniher had stated that "he [Lamb] will be back", Lamb only played two more games in 2003 and it appeared that he had lost favour with the Melbourne coaching staff, as the Melbourne defence was lacking in height and strong bodies, which Lamb could have provided. His last game was against Adelaide. Crows forward Ian Perrie kicked two goals on Lamb in the first quarter and he was benched for the rest of the game.