For the record, Necas has never played center for Carolina. There have been opportunities to try him there and the coaches haven’t done it. I trust their player evaluation enough to feel like that’s because he’s just a winger at the NHL level.
If they have to make a choice between the two long-term, they will pick Jarvis. Necas has game breaking speed, but Jarvis is the more well-rounded player. His current usage says it all (shutdown minutes with Staal, 1st PP, a regular PK shift). Fortunately, they don’t have to make that decision right now or even this Summer.