We propose a seesaw scenario that possible corrections to the tribimaximal pattern of lepton mixing are due to the small phase splitting of the right-handed neutrino mass matrix. we show that the small deviations can be expressed analytically in terms of two splitting parameters($delta_1$ and $delta_2$) in the leading order. The solar mixing angle $theta_{12}$ favors a relatively smaller value compared to zero order value ($35.3^circ$), and the Dirac type CP phase $delta$ chooses a nearly maximal one. The two Majorana type CP phases $rho$ and $sigma$ turn out to be a nearly linear dependence. Also a normal hierarchy neutrino mass spectrum is favored due to the stability of perturbation calculations.