Blackburn forced to move for Aberdeen defender Anderson amid rival interest
The Lancashire Telegraph says Anderson was first recommended to Rovers in the summer and was given a trial under previous boss Sam Allardyce, playing in a pre-season friendly at Southport.
A club source says they continued to be interested in the free agent and, with other clubs showing an interest, opted to capture him on a pre-contract deal in January.
Despite his limited experience in professional football, manager Steve Kean believes Anderson possesses the raw talent to develop into an established Premier League player.
He has pointed to the late development of Manchester United defender Smalling as evidence players can be late starters after he moved from non league Maidstone to the Premier League in three years.