Cardiff will allow long-serving Kevin McNaughton to leave this summer along with Danny Gabbidon and Nicky Maynard.
Highly-rated Atletico Madrid midfielder Saul Niguez has signed a new five-year contract.
The Rugby Park outfit have been linked with the Saints number one as they seek to strengthen the position ahead of next season.
Inverness' Antonio Reguero is close to finalising a pre-contract agreement that will see the Spaniard join Killie on a two-year deal.
Shiels is keen to find another goalkeeper but says Mannus is not one of the names on his wanted list and that he is not preparing to make a swoop.
He said: "Definitely not, that wasn't mentioned.
"I think he's a great goalkeeper and I always did think that. But people have just plucked that out of the air because he's from Northern Ireland.
"There have been no approaches made for the goalkeeper. I didn't even know he was out of contract."
With Cammy Bell set for a move to Rangers and Kyle Letheren released last week, Shiels is keen to bolster the goalkeeping position.
He added: "Yes we will be looking at that. I've got a few irons in the fire so to speak."
On Reguero's deal, he said: "It's almost there."