Warwickshire have already made a formal approach for the former Pakistan leg-spinner, who will be out of contract at the end of the season.
Mushtaq has proved to be a potent asset for the Sussex, snapping up 427 wickets in 75 first-class games with the county champions.
But Sussex skipper Chris Adams is not willing to let go his spin star so easily as he is likely to be retained ahead of paceman Rana Naved as the county's sole overseas player next season.
The Pakistani duo are both out of contract at the end of this season and one of them will have to be off-loaded as counties will only be permitted to play one overseas player from the 2008 campaign onwards.
Both have played an important role in Sussex's recent success but Adams believes 37-year-old Mushtaq will get the nod ahead of Naved. Adams said, ''Mushtaq's contract is up, as is Rana's, at the end of the season. One of them will be retained. I suspect, if he is still hungry and wants to remain a Sussex player, then it will be Mushtaq.
''Is he keen to stay? You will have to ask him. All I can say is he loves his cricket. He has worked hard on his fitness.
''He won't mind me saying he turned up this season less than 60 per cent of what he is normally used to being physically and mentally fit.
Referring to the Bob Woolmer episode in the World Cup, where Mushtaq was the bowling coach, Adams said ''He went through quite an horrific experience at the World Cup (the death Woolmer).
''It took him a while to get himself up and running and he has worked very hard at his physical fitness and that makes a difference in terms of how you enjoy the game.
He, however was quick to praise the star performer, saying ''Mushtaq has been outstanding for this club. He even really enjoys Twenty20 cricket.
Andrew Flintoff's return to County Championship action was spoilt as Pakistan duo Mushtaq and Naved combined took four and three wickets respectively to put Sussex on top of the English county championship and spoil Flintoff's return to duty.
Sussex clinched a 108-run victory at Liverpool.
Flintoff was out for nine as Lancashire, set a target of 242, crashed to 133 all out.