How hard do I have to throw to go D1? Or some variation of this topic is constantly being discussed.
For a RHP, generally speaking, you have to throw hard. And velocity is not the only benchmark, but it's a very important one.
PerfectGame is one data point. I know that not all players do PG events. My youngest is a college player and did not. My oldest was a D1 RHP / SS and only did one PG event.
That said, if I read PG profiles correctly, the average fastball for 2017 grads clocked by PG in 2017 is 82mph. 84mph would put a 2017 roughly in the top 45% in 2017. I'm not looking at all the data, but I'd swag 82-83mph would put a 2017 at the median fastball, i.e., the 50th percentile, in 2017.
2017 RHPs at or below the median of 82-83mph are generally not going to play Division 1 baseball as a pitcher. It's possible. Anything's possible. Generally, in my experience and IMHO, 87 - 89 mph is a decent starting point for the discussion of a D1 RHP. There are always exceptions.