Javier Mascherano claims to have no idea why he was sent off against Manchester United during Liverpool's 3-0 Premier League defeat at Old Trafford.

While the possibility persists that the Argentinian could yet have to serve more than the mandatory one-match ban — because he failed to leave the pitch immediately after being red-carded — Mascherano remains non-plussed over the initial reason for yesterday's dismissal.

Referee Steve Bennett had already booked him for a foul on Paul Scholes when Mascherano sought to make his feelings known to the official after Fernando Torres had also been given a yellow card.

It was then the referee gave the midfielder his second booking for dissent.

But Mascherano claimed today: "I do not know why I was sent off.

"I asked the referee what was happening. I did not swear; I was not aggressive and I did not confront him.

"All I did was ask him what was happening, nothing else."

Mascherano, who subsequently lost his cool as he made his way off the field, told the Liverpool Echo: "When he showed me the second yellow card and sent me off I could not believe it.

"I am sorry to my team-mates because that meant we went down to 10 men — and that made things even more difficult for us."

Mascherano could yet face a lengthy ban, according to a Football Association (FA) spokesman.

The dismissal carries an automatic one-match suspension but the FA can sanction Mascherano further for his refusal to leave the pitch immediately after being sent off.

"When the player refuses to leave the field promptly, we do have mechanisms (for further punishment)," FA press officer Andrin Cooper said. "We can act on anything the referee has not seen or is outside his jurisdiction," he added of FA powers to view incidents further.

"The referee has done all he can under the laws (of the game) up to that point," Cooper said, referring to the sending off. "Any subsequent action is outside the referee's jurisdiction.

"(Further action) is a possibility but we won't be able to say anything about that until tomorrow (Tuesday)."