Aston Villa have raised concerns with referees' chiefs about new rules regarding injuries and substitutions.

Any player who receives medical attention on the pitch must leave it and remain on the touchline for 60 seconds, meaning their team is reduced to ten for that period.

And if a player takes more than ten seconds to leave the field after being substituted, his replacement is not allowed to enter the field until the first break in play after a minute has elapsed.

Daily Mail Sport understands Villa are not the only Premier League club to raise concerns with refereeing body Pro Ref this term. The feeling among these clubs is that referees are not using sufficient judgment to determine when a player is genuinely injured and when he is wasting time.

Unai Emery's men are looking for their first Premier League win and goal of the season after they got off the mark in the Champions League at Club Brugge in the week.

One of the club's most eye-catching signings this summer was Alejandro Garnacho, who joined on an initial loan deal from Chelsea – days after Morgan Rogers moved in the opposite direction for £117million.

Garnacho has struggled to rediscover the level of his early days at Manchester United and Emery needs to see more from the 22-year-old, who has played for only 31 minutes until now.

Emery said: 'His attitude is positive. Now he needs time and hard work every day and he is showing it. It's most important to be consistent and demanding through his attitude, and then eventually he will achieve his best level.'