A system for heating fuel in a combined cycle gas turbine includes a fuel heat exchanger downstream from a turbine outlet, and the fuel heat exchanger has an exhaust gas inlet, an exhaust gas outlet, a fuel inlet, and a fuel outlet. A first exhaust gas plenum has a first exhaust gas inlet connection between the turbine outlet and a heat exchanger and a first exhaust gas outlet connection upstream from the exhaust gas inlet. A second exhaust gas plenum has a second exhaust gas inlet connection downstream from at least a portion of the heat exchanger and a second exhaust gas outlet connection upstream from the exhaust gas inlet.