Christian Fuchs should have been booked for throwing the ball at Alexis Sanchez "on purpose" during Arsenal's 1-0 win over Leicester, says Arsene Wenger.
As Leicester chased an equaliser, defender Fuchs took a throw-in and seemingly aimed the ball at Sanchez.
The Chilean, who went down theatrically after a short delay, was booked for standing too close to the throw-in.
"Fuchs was lucky not to get a yellow card because he threw the ball at him on purpose," said Arsenal boss Wenger.
The ball hit Sanchez on the shoulder, but the 28-year-old fell to the ground clutching his face and was shown a yellow card by referee Mike Jones for not retreating far enough.
According to the Football Association's 'Laws of the game', law 15 states that "opponents must stand at least two metres from the point at which the throw-in is taken".
"In the first two attempts when Fuchs tried to throw the ball in, Sanchez stood next to him and didn't know he had to be further away," said Wenger.
"Also the referee did not tell him to move further away and after that he got a yellow card because he didn't accept the rule. I accept that. He was not the required distance. The referee or the linesman should have told him."
Sanchez later posted pictures on Twitter of his split lip, but Wenger revealed that it came from a separate incident, which he was similarly unhappy about.
"Robert Huth went really in with him I think," he added. "I helped him to get up and he was bleeding on the lips."