We study equilibrium statistics of single semi-flexible polymer chain in the presence of defects. The defects are lying along a line in the two and three dimensions and the monomers are interacting with the onsite potential of the defects. A fully directed self-avoiding walk model is used in the two and three dimensions to describe thermo-dynamical behaviour of the chain in the presence of m (≥1) defects. We propose that the number of conformations of the semi-flexible polymer chain may be controlled by means of introduction of such defects so that a particular fraction of the chain conformations may be either suppressed or populated as per our requirements for synthesizing the polymer-nano-aggregates. We discuss the role of annealed defects for its Q (>N; number of monomers in the chain) realizations and m defects analytically, i. e. when the defects are in the thermal equilibrium with the monomers of the semi-flexible chain.