Yes a bad throttle position sensor can cause a vehicle to be hard to start.
When a throttle position sensor isn't working properly it won't let the computer know properly where the throttle is positioned and allow to much or not enough fuel to get to the throttle body which could cause it to not start either due to not enough fuel or too much fuel entering the throttle body.
Other things that can cause hard starting of a vehicles engine are clogged fuel filter, bad fuel pump or even a bad coolant temperature sensor.