Aston Villa caretaker boss Kevin MacDonald was "disappointed" by referee Mike Dean's decision not to allow immediate treatment to Ashley Westwood after he suffered a head injury.
Midfielder Westwood was caught in the face by Mousa Dembele's flailing arm and went down injured in the first half of Monday's 3-1 defeat at Tottenham.
Play continued for about a minute before Dean ushered on a doctor.
"I'm glad it wasn't more serious," MacDonald said.
"It's a bit of disappointment the referee played on. Ashley had blurred vision - concussion. He's got a real bad headache but he's up and not so dizzy right now."
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With new Villa boss Remi Garde watching from the stands, the 25-year-old was forced off in the 38th minute and, once team doctors had treated him by the side of the pitch, they asked for paramedics to be called.
Former England defender Danny Mills, who was at White Hart Lane as part of the BBC Radio 5 live commentary team, said: "I'm surprised at Mike Dean. It's a flailing arm. Dembele clearly hit him in the face and Mike Dean played on for a good minute or so. The referee clearly got that one wrong.
"If it is concussion then questions have to be asked of the referee. He was looking at the incident - he must have been looking right at it - he saw the player go down holding his face and didn't stop the game."
The Premier League introduced new rules on how to deal with head injuries from the start of the 2014-15 season after Tottenham were criticised for letting keeper Hugo Lloris continue playing after he lost consciousness in a goalless draw against Everton.
A player suffering a head injury must now leave the pitch and the club doctor must decide if a player is capable of continuing, not the team management.