Odisha Chief Minister Naveen Patnaik on Monday sacked a third minister amid speculation that more heads are likely to roll soon.Housing and Urban Development Minister Sarada Prasad Nayak was shown the door three days after Patnaik dismissed two other ministers Anjali Behera and Sanjeev Sahu for allegedly conspiring to topple his government.The Chief Minister, who was away in London, had cut short his visit in the wake of the dissidents' threat.