Your stock doesn't drop from moving to a more athletic position.
If he was a "potential top 50 pick" at Guard then playing Tackle (a more athletic position) would only help his stock.
And NFL coaches have access to all of Washington's film. They could watch every play he had at Guard.
By all means, tell me again about how struggling out of position can only help his position. I can usually agree with your points, but you're dead wrong on this one. Maybe it normally works otherwise, but not in this case.
04/29/2012 - A closer look at the Eagles' picks: Round 6/200 - Brandon Washington, G, 6-3 320, Miami...
After thriving inside two years ago, Washington moved outside to tackle last season and struggled, which was a big reason he lasted this long. Eagles plan to move him back inside. - The Sports Xchange
12/07/2011 - The "open season" date for agents to begin recruiting underclassmen as possible early entrants into the 2012 NFL draft is Thursday, December 1st.
At least one possible top 50 pick isn't waiting that long to announce that the agents might as well not even bother; he's returning for his senior season. Miami offensive lineman Brandon Washington, a 6-4, 330 pound junior with high level starting experience at left tackle and left guard, told beat writers that he's coming back. "Yes, I'm going to be here," Washington said emphatically, adding "because I see the change in the program, I see the change in the kids and I see how everybody's buying in." Washington hadn't received the national attention of a David DeCastro (Stanford) or a Cordy Glenn (Georgia), but like these two men, he was being projected as a possible first round pick. Washington claims that he may not even submit his name for a grade from the NFL Advisory Committee because he is so firm with his decision. He cited the fact that in returning to school, he'd be on pace to graduate - an accomplishment that no one in his family had previously been able to do. Though Washington played well outside at tackle, most project him back inside at guard in the NFL. Washington has a short, stock build. He is surprisingly light on his feet and plays with intensity and physicality. The feeling among scouts is that Washington could play outside at the next level, but he could become a Pro Bowl caliber guard. - Rob Rang, NFLDraftScout.com