Mawene struck up a hugely successful partnership with St Ledger last season as North End reached the Championship play-offs.
Republic of Ireland international St Ledger has been linked with a number of clubs over the summer, including Everton, Burnley, Celtic and West Brom.
And Frenchman Mawene told the Evening Post: "Ledge is doing very well here - he's in a different class, to be honest.
"He's got pretty much everything going for him. Hopefully Preston can keep him for longer, from my point of view he has been a pleasure to play alongside in the defence.
"But chances to play at a higher level don't come along too often and a footballer's career is a relatively short one. Sometimes players have big decisions to make."