The 96-time Australia international is currently a free agent after leaving Omiya Ardija in Japan last year.
Neill made 188 league appearances for Rovers between 2001 and 2007 and the 35-year-old has been training with the Ewood Park club since November.
"Lucas and myself have been very honest with each other right from the start, we both know where we stand," Bowyer told the Lancashire Telegraph.
"If the opportunity for Lucas to join another club comes along then that is a possibility.
"But at the same time we would have to sort something out if we thought something suited us."
Only Queens Park Rangers, Burnley and Brighton & Hove Albion have kept more Championship clean sheets than Blackburn this season.