Sergio Perez in Spain will have to serve a 3 place penalty on the starting grid. His return to the pits with a "visibly damaged" car after the impact with the barriers on the 53rd lap of the Canadian GP it was deemed potentially dangerous by the commissioners. Perez's move, however, does not seem to have been his own initiative, but rather a request from Red Bull. The team in fact asked Perez to bring the car to the garage for immense damage Max Verstappen's race.
Red Bull admits asking Perez to return
After Monaco Sergio Perez had to deal with another disastrous weekend. After qualifying in sixteenth position, the Mexican was unable to move up in the race. In the final stages of the GP he also had to retire due to a heavy contact with the barriers which destroyed the rear wing of the RB20. Despite having a rear that was losing pieces, the Mexican covered more than half a lap to manage to return to the pits. Thus avoiding another Safety which would have put Max Verstappen's leadership at risk. The "cleverness" of Red Bull, who admitted the irregularity of the matter, cost Perez 3 penalty positions. The Mexican will have to serve them for the next GP in Spain. The team, being responsible for Perez's return, was also sanctioned with a fine of $25.000.

Il statement of the stewards specifies that: “After coming into contact with the barriers at Turn 6, the driver [Perez] continued on the track for the rest of the lap with a significantly damaged car and therefore lost several carbon fiber parts on the way of returning to the track. The team confirmed at the hearing that the driver had been advised to return the car to the pits because he was trying to avoid a Safety Car situation. The Stewards determine that, in addition to a financial penalty for the team, a sporting sanction is also necessary due to the safety implications of the incident.”
A useless move, considering that Safety still went out due to another accident. But that makes us understand even more how much Perez is a team player in all conditions.