A combined cycle power plant startup system is provided. The system includes a steam turbine, a HRSG, a condenser, and a bypass system. The steam turbine may include a turbine section. The HRSG may be operably connected to the steam turbine for providing steam to the steam turbine. The HRSG may include a reheater. The bypass system may be configured to adjust the steam pressure downstream of the reheater by routing steam downstream of the reheater to the condenser. The bypass system may include at least one bypass line, at least one control valve operably connected to the at least one bypass line, a pressure gauge configured to monitor the steam pressure downstream of the reheater, and a controller configured to communicate with the pressure gauge and operate the at least one control valve.