There is no way to make a perfect track conversion, but here's the way I break this stuff down.
Receivers with this kids' build typically improve on their 40 times around 0.2 seconds per year in high school. But Butler only has two times posted. The time of year also factors into this. Athletes run better times in the summer. Anyway, he improved by 0.3 seconds from his sophomore to junior year. If we conservatively give him a 0.2-second improvement in his senior season, that puts him at 10.9 100 meters.
A 10.9 converts to a 4.54 forty-yard dash. It's not a perfect conversion, but it's worth noting.
He posted a 7.07 60-meter time. That converts to a 4.43 forty-yard dash.
If you watch his tape, look at his frame, and take into account that the kid isn't a full-time track star, it's easy to see he could improve his speed in college. It's easy to speculate he's faster than his limited track times.
He shows excellent balance and field vision on film.
Many on here thought Deandre Moore was slow, but I remember looking into that last year. His 100-meter conversion put him at 4.55 in the forty with a running back frame. That is on the high end of what I would call an acceptable time, especially for a physical slot.
In the Herman and Strong tenure, we recruited "4-star" receivers who couldn't break 4.7 in the forty. That's a very big problem, especially if they don't have size. These recruiting services have no idea what they're doing.