Happens quite a bit in the NFL. Seahawks did that with Bruce Irvin. Drafted him as a speed rushing DE. Didn't work well out for him with his hand on the turf, so they moved him to an 4-3 speed OLB and he did well in the transition.
Hawks are notorious for drafting a player at one position and having him start at another. I think half of the OL was drafted as DL players.