Malky Mackay has warned Pompey that Peter Whittingham is not for sale.
The Blues recently had a £1m-plus bid turned down for the 26-year-old Cardiff star.
Steve Cotterill sees him as a player to strengthen the left-sided options in midfield.
Two Premier League sides have also been chasing the former Aston Villa man, who has made more than 200 appearances for the Bluebirds.
But new Cardiff boss Mackay has insisted Whittingham is not for sale.
Instead he expects the player to have a key role in his team.
And it will come as a blow to Pompey fans, who would love to see Whittingham at Fratton Park.
Mackay said: ‘Peter Whittingham is a fantastic footballer and I can understand why other clubs would look at good players.
‘But he is a Cardiff player and he is staying a Cardiff player.
‘We’ll keep working on strengthening the squad.
‘I will be on the phone every day and working to get more players into this football club as quickly as we can.
‘And Peter is central to my plans.’
Nottingham Forest attempted to tempt Whittingham away last season.
But he instead signed a new three-year deal and enjoyed another impressive campaign as Cardiff reached the play-offs.
They have already lost 12 players from their squad after last season, including Craig Bellamy, Jay Bothroyd and Michael Chopra.
Those that have arrived are Craig Conway, Don Cowie, Andrew Taylor and, this week’s signing, Robert Earnshaw.
Mackay will now try to keep Whittingham as he looks to build on what Dave Jones achieved.