The absolute truth is the WLB and MLB are basically the same position in our system whereas SLB is significantly different - and without a doubt - Wagner could play them both well. In fact, Wagner is probably more suited to play weak side backer than in the middle. Wagner is smallish to engage blockers but would ideal for going sideline to sideline without engaging many blockers.
So I actually see grabbing a larger MLB as a major possibility.
Moreover, this notion is seconded as we very badly require depth for Wright. Wagner is far from ideal for playing SLB. He doesn't have the length to engage and jam TEs on a play-by-play basis. He also probably doesn't have the leverage to play on the LOS. This would be another reason for drafting a larger LB and moving him to the middle while Wagner plays outside.
Mark my words - if we can grab a Dont'a Hightower type LB in the first round - we will.