Have you been paying attention? Tonight Ryan Kalish played center field for the Sox. His box score (3 0 0 0) does show much of an impact, does it?
Early in the game, Kalish fielded a base hit into the gap and gunned the runner out at second, possibly saving a run. Historically, we've had some weak arms in center (Damon, Crisp, Ellsbury), so this is at least a temporary upgrade. Later, with runners on first and second and no out, he executed a sacrifice bunt perfectly, advancing the runners, who then scored on a Scutaro single.
So, with "nothing" in the box score, Kalish made a significant contribution both offensively and defensively. Seeing is believing.