Don't quite get your question
If you are asking, whether it is normal for a SS to throw harder from the infield than they would on the mound. I suppose yea, its normal, especially if you are not acclimated to pitching off the hill, Pitching is a completely different art, and throwing hard on flat ground, IMO doesn't always translate into throwing hard on a hill.
If you mean do position players in general throw harder than pitchers, than yea, I suppose so.
For example, Miguel Olivo, catcher for the Marlins was clocked at 98 MPH throwing to 2nd base.
Players like Reyes and Furcal have strait up Cannons, and Vlad is right there with them. Just a few off the top of my head.
While as, the average pitcher velocity is about 90, give or take.
Hope it made sense
~Dan