At least Kelly could play the PK, be strong on the draw and play a good all round game.
That's part of the issue with Belesky, even when he was playing decent back in the 1st 2/3rds of his first season here.
He has basically no special teams role.
He's get some time on the 2nd PP unit, which typically gets 40-45 seconds each PP.
But what's his role? His puck skills are poor, he's basically a shooter with only an above-average shot. At lot of his goals are more about catching the goaltender off-balance or off his angle, he's not a sniper who has range and picks corners.
So he's basically a net-front presence, which on the 2nd PP unit that job is taken up by Backes.
He doesn't kill penalties, although one would think he would be capable of doing so.
I commend him for changing his diet and off-season regime. Even prior to his knee injury, he appeared pudgy/out-of-shape and always a step behind the play. Losing weight should help him in a number of areas, and shouldn't impact his physical play. If anything, a quicker first step with the weight lose should help him land hits before his opposing player gets out of the way.
Cassidy has a challenge ahead of him with Belesky. He almost has to find a special teams role for him if he's a regular in the line-up. I'd recommend making him a PKer. I see no place for him on the PP.
And he also has to find proper linemates for him. Him with Spooner as his center has been a disaster. Doesn't work, we'll see where he ends up.
And he's got competition, and will need to play decent to stay in the line-up.