His ES minutes weren't anything out of the ordinary last year. 4th in the league per game. 20 more seconds per game than Zetterberg with a bad back. #2 in total ES minutes. 20 more minutes than Crosby. With Kopitar's cap hit, he better be able to play a lot. It's built into the price. He also took more faceoffs than he ever has too. They were probably throwing him out there just to take one on occasion, because without Carter, they couldn't trust anyone else. Took more faceoffs than almost the next 4 Kings combined. Next was Kempe, and he was awful. Go back to 09-10, and last year the Kings had their worst team faceoff winning %, and that was with Kopitar at a career high %.
Overall though, yeah, Stevens doesn't do a 4th line. 41 forwards have have played between 16-17 and 17-18, and 11 of the bottom 12 in ES minutes per game, and 5 of the top 8, were from last year.
Kopitar playing a lot though, whatever. He was the 4th highest paid player in the league last year, 3rd highest cap hit. This year, tied for the 4th highest paid player, tied for the highest cap hit. They can't afford a more proven 3rd line center in part because Kopitar got paid. Take less money if the burden is too big. He had a hell of a year carrying the offense though. Not saying he shouldn't play a little less, if possible, but it's a hard cap league, and guys like Stoll and Handzus have been difficult to replace.