raheem sterling has rejected a new contract worth £ 100,000-a-week .
liverpool boss brendan rodgers says sterling wo n't be sold this summer .
his achievements at 20 are not on the same level as some anfield greats .
steven gerrard won three trophies in the first year out of his teens .
michael owen had scored more than 50 career goals for liverpool .
sterling has a long way to go if he is to fulfil his huge potential .