This comment makes me think you have an agenda against Tosun. He plays well but gets overshadowed a bit by the speed merchants around him. I think he adds perfect balance to our attack. He may not score as many as the Ricki/Theo/whoever axis but he plays an essential part. What he isn't, in this league is an out and out goalscorer. He will convert a fair amount of chances, but his link play is very good, and compliments the others up front perfectly. I should imagine Silva sees lots in him besides goals. I think his place is determined by the goals being scored around him, not necessarily his own goals total.
His role is to defend the near post and the root of all our problems is losing the flick at the near post. He is constantly static. We need someone commanding to deal with it at source. If Tosun can't do it then the manager needs to choose someone else.