At the time, Vertonghen was treated by medical staff and cleared to keep playing. But soon afterward, he staggered to the touchline and had to be helped off the pitch, keeling over and retching.
“That’s the first time I’ve said that now. I shouldn’t have continued to play on and I was struggling for a total of nine months and I could therefore not bring what I wanted (to the pitch).”
The response was prompted when Vertonghen, 33, was asked about being substituted in the first-half of Tottenham’s Premier League game against Southampton earlier this year.
It appeared the Belgian international was frustrated at Spurs coach Jose Mourinho during the game in February, but he now says it was anger at his own performance due to the lingering effects of the head clash.
“At that substitution, everyone thought I was angry with Mourinho, but at that point I just couldn’t (continue) anymore.
“I still had a year contract, so I had to play. But when I played, I played badly. Not many people knew that, that was my own choice, I am not blaming anyone.
“I just didn’t know what to do. It was game after game and practice after practice. Each time there was a new impact.
“Then the lockdown came and I was able to rest for two months and afterward it was better.”
Vertonghen joined Portuguese club Benfica on a three-year deal in August having spent eight years with the North London club.
CNN contacted Tottenham for comment but did not immediately receive a response.
At the time, the club said its medical staff strictly followed the English Football Association’s concussion guidelines. Vertonghen was judged to be alert after the incident and responded to questions “correctly and lucidly,” according to Tottenham.
Mauricio Pochettino, who was then Spurs manager, said his medical staff and the referees were “excellent” and followed the correct protocols, while Tottenham also said Vertonghen had undergone further tests and seen an independent neurologist, after which it was judged he did not suffer a concussion.
“In many cases, these symptoms resolve themselves within a few days or weeks. However, in some cases problems can persist for months, but still resolve themselves eventually,” says Headway.
On Wednesday, the International Football Association Board (IFAB), football’s rule-making body, agreed to trial additional substitutions when players leave the field with a concussion from January 2021.
“The members agreed that, in the event of an actual or suspected concussion, the player in question should be permanently removed from the match to protect their welfare, but the player’s team should not suffer a numerical disadvantage,” said a statement from the IFAB.
CNN’s Rosanne Roobeek contributed to this report.