This is a story about rookie 49ers right tackle Mike McGlinchey. But any tale about McGlinchey must also feature veteran Joe Staley, his counterpart at left tackle, for reasons that this piece and a video of the two singing a boy band hit will illuminate.



So, let’s begin by rewinding all the way back to 2004, when Staley was a college sophomore at Central Michigan.



New head coach Brian Kelly and offensive line coach Jeff Quinn, both of whom would eventually move on to Cincinnati and eventually to Notre Dame, where they would work with McGlinchey a decade later, had just converted Staley — formerly a lanky 220-pound high school tight end — to offensive tackle.



“When I first got moved, I was pretty upset,” Staley said in a recent interview with The Athletic. “I seriously thought about transferring just because I was so light. I just didn’t see it at the time.”



When spring practice rolled...