Football has a long history of clubs buying successful players then playing them in a different set up contrary to their previous set up where they thrived . A high scoring centre forward who fed off his other forward suddenly becomes a solo target man and fails to score. Likewise the high scoring forward who feeds off through balls is bombarded with high crosses and is sold on as a failure. Etc . It's not really difficult to understand but clubs still get it wrong!
It could be that apart from being an experienced professional he actually does what the Coach / Manger asks him to do so I'm all in favour of his return on the lines of Mick Channon who was brilliant at Man City and very good for Saints .