It depends where Reid, Marsh and Moore all are at come the end of the season.
Right now I am happy with Brown and Frost as our KPD's... Its arguable how much of an upgrade Carlisle would be on either of those guys. If Reid gets back to health/form, then i would have him as the 3rd tall defender... And I dont think we have a need for Carlisle (partucularly at the suggested rate).
But if Reid doesnt recover, and/or if Brown has more injury issues then we would clearly have room for someone. (unless Marsh steps up when given the opportunity, or Moore doesnt get transitioned into a forward).
As others have said, until the WADA case is done, i would be very reluctant to offer much, both in terms of trade and salary.