It is highly unlikely Wenger's absence
from the bench will have any impact on the players, he basically does his coaching before the match and halftime, he hopes his players follow his
instructions whether the opposition made a
tactical change or not.
In case you are looking to accuse him of
tactical ineptitude, Wenger has never been a coach to micromanage his players on the pitch, even during the season they went unbeaten, he simply got intelligent self motivated players together who communicated with and led each other on the pitch, figuring out opponents and outwitting them without waiting for
instructions from the bench, Henry, Pires, Vieira, Adams, Keown, Campbell come to mind here.