Yeah, I only see Gryz sneak down the wall to keep the puck in most of the time, then he'll quickly go back to the point. I think the coaches have encouraged him to get more involved in the offense because they want him to be an offensive defensman, but he naturally is very defensive minded. Always making the safe play, and trying to keep himself between the puck, and his goal.
I agree that, for some reason, Monty likes Forbert more than Gryz. I can't say why. From the games I've watched Gryz is just better. Even on the PK, Gryz seems to prevent far more high quality shots, can intercept cross crease passes better, and is more attentive at tying up players' sticks in front of the goal so they can't tip the puck.
Forbert is big, and can block some shots, but is just too slow to follow the puck when it's moved quickly. If our goalies weren't so good, I don't think Forbert would be so highly regarded on the PK. He was a pylon against Florida last playoffs, and that didn't work out so well for Monty, and the B's.
Gryz, and Mac just work so good together, I hate to break them up.
That being said, any player is tradeable for the right return. I'd trade him if a need like #1 center was available.