A Schottky contact detector comprising a symmetric metal stripe buried in Si, capable of detecting surface plasmons at wavelengths below the bandgap of Si, is described. A model for the detector is proposed, and its performance is assessed at lambda(0)=1550 nm assuming a CoSi(2) stripe in p-type Si. End-fire coupled responsivities of about 0.1 A/W and minimum detectable powers of about -20 dBm are predicted at room temperature.