JB is a great guy in the locker room and his leadership quality will be greatly missed if Isles end up trading him. Besides the coach you need leaders (more than one) to gel the team so they can perform as a team. Isles have a few of these guys but some of them may not come back this year and the following (Martin ufa this year and Cizicas after this season).
The main reason why they need to move him is that Isles is loaded with RHD D (roster and prospect) with the need for clearing cap space so they can keep the younger assets like Pulock and Toews. JB has always been one of the most reliable RHD PK Ds on the Isles team as he still can box out forwards in front of the net, block shots, and shoot the puck far down the ice on every first chance of clearing, which neither Pulock and Mayfield can do consistently as well. He is also a very smart player and does make good decisions on ice most of the time and still has one of the best shots from the point on the team that can either beat the goalies or assist on deflections. The problem is that he has been injured quite a bit in the last two years so his value will depend a lot on his health.
Dobson needs to play on the right side and it is tough for Isles to insert him into the lineup consistently with RHD Pulock, JB, and Mayfield all on the roster this coming season, thus someone has to go. Mayfield's contract value is too good especially in today's flat cap to pass up until Wilde is ready to replace him possibly in 2 or 3 years. Pulock can be traded for top picks, a very good 1st or 2nd line winger, or blue-chip prospects but as he is homegrown, still has not yet reached his ceiling and has great chemistry with Pelech, I doubt that they will go that route.
