Deuterium nuclear magnetic resonance line splitting arising from deformed cis-1,4-poly(butadiene) network, of which the network chain concentration is varied by incorporating protonated free chains of similar kind, is investigated. The results are discussed according to the theoretical framework, introduced by Brereton and Ries,(1) which dealt with network vectors which were treated as quenched variables, to show explicitly how they collectively determine the anisotropy in the mean field. The influence of the network chain concentration on the NMR line splitting and molecular weight dependence of Flory interaction parameter chi and the possibility of using the deuterium NMR line splitting to investigate chi parameter of a system are discussed.