It's not going to be Karlsson if the Penguins trade with Vegas. I think it's going to be Eakin if I had to guess. I think Karlsson is way too good for Vegas to trade, Haula is playing too well and has too good of a contract to trade and Lindberg isn't quite good enough for the Penguins to trade Cole for. But Eakin, I think that makes a ton of sense. Eakin has basically everything you want out of a 3C, he's peak Hagelin if Hagelin played center. His possession stats are mediocre, but he gets a ton of ES points, is very reliable defensively, kills penalties and is laser fast. He'd be a good target for the 3C spot, he's just as good as Bonino is. It's just a question of how do you fit his $3.85 million cap hit here? That's fair for him, but that's pricey for the Penguins.
The nice thing about Eakin too is that he can play wing, so if Sheahan suddenly explodes into a 3C, you can have Eakin on LW with Kessel and have that wing duo be really effective. My concern is if he ages similarly to Hagelin. Hagelin fell off at age 28, Eakin will be 28 in the last year of his contract.