Nelly attended University City HS, just outside St Louis, which hasn't been a significant source of baseball talent in three decades. I live about 20 miles away. So far this year their record is 0-17! He went there in the mid/late-90s, tho.
Like many celebs, his athletic record is found mostly in his own press handouts.
They say he "was scouted" by major league teams, but no stats are offered to verify his talent. Some online sources say he was "offered a chance to play professionally."
Yet, I havent found a single online source that mentions what position he played.