Carlson is also an all around defenceman and while hes sitting tied for 7th in PPG at 0,69 per game over the last 3 years(With Subban and Gostisbehere) for defencemen hes also the defenceman with the 26th most PK time in the league during those years and the Caps second most used after Niskanen on the PK. Of the top nine only Josi have more PK time and has 0,71 PPG almost tied with Carlson. Only Hedman of the other players is close in PK time to Carlson over those years with 517 minutes to Carlsons 552. Then you have PP specialists Gostisbehere and Klingberg who does not PK. The rest are used some on the PK(Karlsson, Burns, Letang, Subban), but a lot less than Carlson. The Caps PK have been the 5th best PK during those years to. So hes not only an offensive defenceman, but a player trusted in all situations.