The 35-year-old left Ewood Park in 2007, but following spells with seven other teams, including West Ham United, Everton and Galatasaray, he is now without a club.
However, the Australian has been training with Rovers since late last year and when asked about the prospect of a potential return for the defender, Bowyer told the Lancashire Evening Telegraph: "I've said all along you can never say never and that is the same situation now.
"Lucas and myself have been very honest with each other right from the start, we both know where we stand. If the opportunity for Lucas to join another club comes along, then that is a possibility.
"At the same time we would have to sort something out if we thought something suited us."
Neill made 227 appearances for Blackburn during his first stint with the Lancashire outfit.