In this article, we consider a type of multi-input-multi-output networked control systems (NCSs) in which the network-induced time delays for different inputs are different. For those unstable and/or poorly damped eigenvalues, we propose a reduced-order memoryless state observer design approach. The full-order state vector of the original systems using the reduced-order observer is reconstructed. We prove that the gamma-stability of the state error. dynamics can be guaranteed. Meanwhile, by computing the residual between the output of the practical systems and the output of the reduced-order observer, the fault-detection scheme of the NCSs is given. An illustrative example shows the effectiveness of the proposed method.