he could probably use a break from Chara, no offense to the big man
I feel like playing with Chara is probably great for him in some ways, but in other ways he has to kind of cover for Chara in ways he wouldn't with someone else. Chara is obviously slow and teams will chip the puck behind him to try to beat him in a race for the puck, and Charlie will have to cover for Chara in those instances and get the puck instead
I'm sure chemistry is a bigger factor for the D pairs, but its odd how often Cassidy mixes up the forwards but he seems pretty insistent on keeping the D pairs together for the most part