I'll give you guys my take on being "quiet" in the locker room.
As somebody who was almost painfully shy as a kid and a teenager AND participated in team sports like soccer and football I can tell you first hand that it's very easy for people to misinterpret your reticence as hostility or indifference. As a result of my own shyness I think I can safely say it had a fairly direct effect on me suffering through a couple of pretty frustrating seasons with coaches who mistook me for a malcontent and a "bad guy."
On a freshmen high-school football team. I didn't hang out with my football "buddies" after practice and I didn't play grab ass in the locker room and I didn't do a lot of "rah-rah-ing" from the sideline or in games. I just played defensive end and I unloaded on guys as hard as I could ... and I was good at it. Regardless, when I got to my sophomore year I'd been pretty much black-balled by coaches (these guys talk to each other apparently) and I could never crack more than spot minutes in games, one assistant even encouraged me to quit "for the good of the team," so I did. My biggest sin? I was told I was too quiet and too much to myself and I held myself above and a part from my teammates -- or at least I was perceived that way. As a result I decided to go into cross-country that fall and focus all my energy on wrestling, two sports that didn't require me to do anything but rely on my own performance and I excelled.
In retrospect I remember feeling misunderstood and slighted and robbed, but now I realize that I caused people to become uneasy around me and that I probably made things very uncomfortable for certain people. If I'd had coaches that only cared about performance on the field, things might have gone differently, but they placed a great deal of emphasis on the brotherhood angle and I think I threatened that a bit.
Part of me can't help but empathize with Miller somewhat in this situation, but I also understand that it's possible that his shyness or "quietness" probably walls him off from his teammates, and for a team that seemed to focus so heavily on chemistry and a collegial atmosphere -- and indeed seemed to feed of this to succeed -- I wonder if it isn't best for both sides that he moves on.