FWIW, Fehr's track record at center is pretty limited. He was a winger his entire career until 2013-14, when he switched to center. Don't get me wrong, the last two seasons he has been a terrific 3C in Washington, but that was essentially on one line with Joel Ward at RW and either Jason Chimera or Brooks Laich at LW. The lines had a very clear identity, where they would cycle the puck (pretty much at will) in the offensive zone. If he can find two wingers he's on the same wavelength with and a cycling line like that can be assembled again, he could resume that style of play. However, if he's centering a line where he needs to be more of a playmaker or take a more proactive approach, it's entering unproven territory.
Granted, he does have a very solid track record as a winger to fall back on if he doesn't fit as a center.