If you search the forum, you 'll find many posts about this. Even a poll from my friend t11 (hi Wahid).
But I disagree. I 'll just give you two examples from today and yesterday games.
In my main team, I had a game 1 hour ago. Starting the game. scoring once, second, suddenly a yellow card, a goal from the opponent and then I realized that he was in the game (from 26' min).
and then a second goal. He didn't change the formation, just with his presence, his team woke.
This thing, when I realize that an opponent manager is coming in the game and his team suddenly improving, happened to me A LOT of times.

My team does better in games I don't watch?-1-22-draw-.jpg