You've just got to play him with Geno. There's no other option. Scratching him is not an option--not a realistic one. Nobody wants to be the coach to end one of the longest Iron Man streaks in the history of the 100+ years of the NHL. We don't give a shit about the streak, but it is a big deal, so just eliminate that option right off the bat. I went over why it makes no sense to play him with Sid; horrible defensive presence forces Jake and Sid, our only really potent offensive guys, to play more defensively. I doubt Sid would be happy with Phil bumbling around and biffing one-timers after Sid draws guys to him to create space for Phil to shoot. Kessel's been bad with Geno all season and he makes Geno worse. There's about a year's worth of evidence of that, going back through last Caps' series. The third line is not an option because Phil's gotten pissed about being "demoted" in the past when he had to play with Brassard. The last thing Phil needs is another thing adding to the frustration of a miserable season, and putting him on the third line is going to do just that.
It's a damned if we do, damned if we don't situation with Phil. Either you play him where he seems the most happy, on Geno's wing, and you neuter the effectiveness of an already banged up Evgeni Malkin, or you play him on the third line with Bjugs and run the risk of the powder keg exploding.
I hope JR at the very least entertains offers for Phil this summer. Not only have his struggles been frustrating as all Hell, he's getting older on a team with a handful of guys (Sid, Geno, Letang, Hornqvist, Kessel) all approaching the inevitable decline due to age. That's nearly $38 million in cap. I appreciate that he's still been able to be a point per game guy in what's been a godawful season in terms of play on the ice. He's still got a lot of skill and a lot to offer a team needing offense. But the bad outweighs the good now as far as Kessel goes, and the Kessel era, as awesome as it's been, should end this summer.