I think Sheppy said he wasn't for trading Carlo because Brandon might sustain yet another concussion.
I'll say that.
Yes, he has size and reach, yes he's been given the "A" for a reason, yes, at his best, he's been a solid defnder, and yes, I'm sure he's the sterling sort.
But, as noted, he's had five concussions thus far, with the next likely ending his NHL career if not seriously jeopardizing his physical & mental health; his play, once ascending, has regressed; I love a stay at home defenseman, particularly with size, but Carlo will never use that size in service of physicality, and does not have, it seems, an offensive bone in his body.
All of that points me in the direction of packaging Carlo with whomever (Reilly, Smith, heck, all three) for "something, anything."
It won't happen, but I woud not mind if it did.
I can deal with a limited but solid Brandon Carlo. I can't live with the same player a concussion away from, frankly, placing the Bruins in another D bind, and most importantly, risking his health.
It ain't worth it. None of it.