They have a lot of talented outfielders. JD Davis, Jeff McNeil, Michael Conforto, Brandon Nimmo, Dom Smith, Tim Tebow (sorry I had to) and they seem to like Juan Lagares in CF.
Even if they don't keep Lagares in CF and they move McNeil to 3B, that's still 4 starting caliber players for 3 spots, so trading an OF is possible.