Goaltending has been atrocious for the Ads, especially Bobkov. Vatanen was playing really well until he got injured. Man, can that kid skate and shoot.
Have you been watching the games, or are you just going by stats? Other defenders like Clark and Lindholm have not exactly been terrible on defense compared to Guenin. Clark plays bigger minutes against stronger opposition than Guenin does. Lindholm's decision making is outstanding, particularly for his age. Guenin is not exactly a 'rock'. He has just been on the ice for less bad goals. The goaltending has been terrible.
Etem has been getting better as the season has progressed. It was pretty understandable that it would take him a while to adjust to the physicality of the league. He will keep getting better the more he plays.
