ThispaperinvestigatesaMultiple-InputMultiple-Output(MIMO)schemecombiningTransmitAntennaSelectionandreceiveMaximal-RatioCombining(TAS/MRC)intime-varyingRayleighfadingchannels.Wefirstpresentnewclosed-formexpressionsforoptimalreceivedSignal-to-NoiseRatio(SNR),whichisexpressedinpolynomialform.Theseareusedtoanalyzeergodiccapacity,outageprobabilityandBitErrorRate(BER)ofTAS/MRCsystems.Numericalresultsarepresentedtovalidatethetheoreticalanalysis.