It’s impossible to say really, without knowing the proper reason it happened. If he genuinely wanted to waste time it was a really, really bad decision. If he wasn’t following instructions or pulling his weight it’s the right thing to do. It’s senior football, you have to be treated as an adult in that environment.
At the end of the day you can say he’s one of the worlds top talents as much as you want, but the opposition just sent a young striker on who won them a point (again), we sent ours on and his biggest contribution was an awful touch followed by a stupid foul. He’s got to actually produce something to justify this reputation he has, so far we’ve seen absolutely nothing.