Sturridge was signed for only one reason and that was to fulfil part of the Champions league regulations which state what players you must have in the 25 :-
An “association-trained player†is a player who, between the age of 15 (or the
start of the season during which the player turns 15) and 21 (or the end of
the season during which the player turns 21), and irrespective of his
nationality and age, has been registered with a club or with other clubs
affiliated to the same national association as that of his current club for a
period, continuous or not, of three entire seasons or of 36 months.
An “association-trained player†is a player who, between the age of 15 (or the
start of the season during which the player turns 15) and 21 (or the end of
the season during which the player turns 21), and irrespective of his
nationality and age, has been registered with a club or with other clubs
affiliated to the same national association as that of his current club for a
period, continuous or not, of three entire seasons or of 36 months.