Embodiments of the present disclosure provide injection systems for fuel and air. According to one embodiment, an injection system can include a mixing zone embedded within a surface of a turbine nozzle and positioned between a first outlet and a second outlet, the turbine nozzle separating a combustor of a power generation system from a turbine stage of the power generation system, wherein the first outlet is oriented substantially in opposition to the second outlet; a first injection conduit for delivering a carrier gas to the mixing zone through the first outlet; and a second injection conduit for delivering a fuel to the mixing zone through a second outlet; wherein the carrier gas and the fuel intermix within the mixing zone upon leaving the first injection conduit and the second injection conduit.