Left-back Hancox has recovered from the hamstring injury which forced him to miss out prior to the international break, with versatile on-loan winger Shane Ferguson now able to push up back into midfield.
Spector was forced off with an ankle injury just minutes into Blues' 1-0 win at Middlesbrough last time out and is struggling to be ready in time for the clash at Selhurst Park.
That means Keith Fahey, who came off the bench for his first appearance since October, could start.
Jack Butland, Nathan Redmond, Callum Reilly, Chris Burke, Paul Caddis and Ferguson are all expected to be fit following their international exploits over the past fortnight.
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- Shane Ferguson