Hamburg: Hamburg SV striker Paolo Guerrero was fined on Monday for throwing a plastic bottle at a fan after the previous day`s 0-0 draw at home to Hanover 96 in the Bundesliga.
The club described the Peruvian striker`s behaviour as "absolutely unacceptable" and said he would face a heavy fine.
"I had a blackout," Guerrero told the club`s website after the latest incident in an unhappy season in which he has also suffered a knee injury and battled against a fear of flying.
"I was insulted and I overreacted. I`m really sorry for it."
"I hope I have the chance to meet the fan in person to apologise. I`ve already apologised to HSV. Naturally, I will accept any fine from the club."
Chairman Bernd Hoffmann said: "Paolo`s behaviour was absolutely unacceptable. That sort of thing should not happen."
"Paolo will be punished by us with a big fine."
Kicker magazine said the fine could be between 50,000 and 100,000 euros (USD 67,370-USD 134,700) and would be donated to charity.
It was only Guerrero`s second league match since he tore cruciate knee ligaments in September.
In January, he was forced to delay his return from a stay in Peru due a fear of flying, media reports saying that he had made several failed attempts to board an aircraft.
He now has to compete with Ruud van Nistelrooy for a place after the Dutchman was signed in January.
Hamburg are sixth in the Bundesliga with 45 points from 29 games, three points off a Europa League place and eight points behind third spot which would earn a place in the qualifying round of the Champions League.
Team captain David Jarolim denied the supporters had turned against the team.
"Paolo made a big mistake in the heat of the moment. But there is no rift between the team and the fans. We must stay together to reach our goals," he said.