Yeah, Jarvis played with Aho in the regular season and his 18.8 shooting percentage was a bit high, but keep in mind he's a full three years younger than Necas. The fact that they trusted Jarvis in his age 21 season to ride shotgun with Aho, play 3 minutes a night on the powerplay, and play 2 minutes a night on the penalty kill (Necas doesn't PK) is really impressive. (Side note - Necas has been stapled to Kotkaniemi which definitely holds him back, but while he's with that anchor over the last three years he gets more than 2/3 offensive zone starts and the primary third wheel on that line has been Svechnikov, so it's not like he's had nothing to work with. Also, weird fact I discovered while looking that up, every player with at least 350 minutes with Necas at 5 on 5 over the last three years has a significantly better xGF% away from Necas than with him. I did not expect that at all and I don't know how to explain it.) Jarvis has also outscored Necas on all three playoff runs he's been on despite the age difference. And at least for this year's run you can't really blame their teammates, because Jarvis has been on the shutdown line with Staal and Terravainen/Martinook and still has 4-4-8 in 9 games.
Anyway, I didn't mean to rip on Necas while talking up Jarvis because I'd be happy to end up with him too and the great part is he can factor into the strategy here. In 2010 when the Blackhawks were in a cap crunch the Sharks offer sheeted Niklas Hjalmarsson, which the Blackhawks matched, but in doing so they put themselves in a position where they had no choice but to go to arbitration with Annti Niemi and then walk away from the award. Then the Sharks swooped in and signed Niemi. The Caps can do that here by giving Jarvis a big offer sheet, and if the Canes match it there's a decent chance they'd have to walk away from an arbitration award for Necas, at which point the Caps could sign him for free!