Javier Mascherano is mystified by his sending off against Manchester United, but has apologised to his Liverpool team-mates.
The Argentine midfielder was dismissed just before half-time in Sunday's 3-0 defeat at Old Trafford for a second yellow card.
Mascherano, who had earlier been booked for a foul on Paul Scholes, was cautioned a second time for showing dissent towards referee Steve Bennett.
He had run 20 yards to question why team-mate Fernando Torres had been booked and was then slow to leave the field after being shown the red card.
Speaking after the game, Liverpool boss Rafa Benitez admitted that he was surprised that Mascherano had been sent off.
Mascherano has now expressed his disbelief at Bennett's decision and insists he did not swear at the official in the incident which saw him dismissed.
"I do not know why I was sent off," Mascherano told the Liverpool Echo.
"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.
"So 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 ten men and that made things even more difficult for us."