Sunderland boss Bruce took Cattermole, 21, to Wigan last summer for £3.5million from Middlesbrough and has tabled around £7m after an initial bid was rejected.
Martinez said: 'It's unsettling and it's very difficult for any human being to deal with. When you're young it is even harder to deal with.
Wings clipped: Cattermole is going nowhere according to Wigan Athletic
'It's the nature of the game, but what you don't want is uncertainty. You need to know where you stand and have players that are focused and working to high standards.'
Wigan are still in talks with Rayo Vallecano over midfielder Mohamed Diame and defender Antonio Amaya.