In this paper, a novel semi-analytical performance prediction method is proposed for iterative MMSE-IC detection and semi-blind channel estimation. It is examplified in the context of single-user MIMO-OFDM transmission which we model by a discrete-input MIMO P-block fading flat Rayleigh channel in the frequency domain. The proposed method extends existing symbolwise Mutual Information Effective SNR Metric (MIESM) link-to system approach to the context of imperfect channel state information and semi-blind channel estimation at the receiver side. It allows to compute the average Block Error Rate (BLER) conditional on an initial pilot-assisted channel estimation and long term channel distribution information. Thus, the proposed method takes advantage of all the available a priori information before actual data transmission and could be equally employed for slow and fast link adaptation.