The Bengals have a young, second-year quarterback in Andy Dalton who led them to a first round AFC playoff appearance in the 2011 season. Dalton, along with more young talent in Cincinnati, is what the Bengals want to build around and bringing in Glenn would be a step in that direction. That's why this has been a steady pick in the mock draft for the team.
Here is what Ryan Van Bibber of SB Nation had to say about the Glenn selection for the Bengals:
"This pick is unchanged from the last mock. Glenn has the makings of an elite lineman. His best position may be guard, but he has the raw athleticism to play left tackle."