Save, the DL I think we would all agree that WR is the biggest concern and that this concern specifically, lies on the shoulders of backup QB Devin Gardner's ability to transition to WR. Well, I played WR in college and like to think I have somewhat of a decent opinion on the position. One thing I learned/witnessed, is that usually big, tall, fast guys, with big hands tend to do well at the position. I do think there is something to be said about timing and learning how to run routes, but from someone who's played the position, I truly believe Devin Gardner has the athleticisim to make an immediate big time impact. Charles Woodson didn't know the offensive play book and still was a serviceable WR option from time to time. Devin Gardner knows where he's supposed to be and when the ball is supposed to be coming from his time at QB which, just knowing a playbook (taken from my personal experience) will greatly help him transition.
A couple more recent transitions I can think of to help prove this point is Ryan Tannehill and Michael Crabtree. Tannehill practiced at QB and redshirted as a freshman. His (RS) freshman year he went all through camp before moving to WR, and by his 5th game went 12 for 210 yds, the rest of his career has been talked about on this blog so I won't drag into it.
Crabtree was a high school dual-threat QB in a similar mold to Gardner. In his first game at the receiver postion a 49-9 victory over SMU, Crabtree had 12 catches for 106 yds and 3 TD's. The rest is history.
I think we all for the most part expect Gardner to be decent to good at WR. I expect him to be great and as Brian would say "undeniable" at the WR position. Just one man's thoughts and opinions, can't wait for tomorrow. Go Blue!