Negotiations for the expected clash between Vitali Klitschko and California’s Chris “The Nightmare” Arreola are at the serious stage now.

“Right now in the talks we are trying to get everyone on the same page and getting this history-making fight made,” said Dan Goossen, president of Goossen-Tutor Promotions, which promotes Mexican-American heavyweight Arreola. “Certainly, I don’t see any impediments on not making it happen.”

The plan is to put the much anticipated heavyweight clash between WBC titleholder Klitschko (37-2, 36 KOs)  and Arreola (27-0, 24 KOs) at the Staples Center in Los Angeles on Sept. 26. HBO will probably telecast the event.

If it transpires, it will be Klitschko’s third appearance at the L.A. venue and Arreola’s first foray at the home of the world champion L.A. Lakers and where Shane Mosley defeated Antonio Margarito last January.

Henry Ramirez, who trains Arreola, said the Riverside heavyweight has been training twice a day in the last month under the guidance of physical trainer Darryl Hudson.

“Chris is working twice a day. First in the morning from nine to 11 a.m. then at night in the gym from 5:30 to 8:30 p.m.,” said Ramirez. “If you can’t get up for Vitali Klitschko you can’t get up for anybody.”

According to various sources, Klitschko’s management team wanted to fight on Sept. 12, the date set for the fight with Britain’s David Haye that fell apart when that fighter opted for Nicolai Valuev. But Arreola’s usual training period would have been curtailed by three weeks.

“We’re only going to lose a week off our normal period, but that’s ok,” said Ramirez by telephone.

When the first date of Sept. 12 was nixed, other offers of October and November dates were discussed. But now it looks like Sept. 26.

“That’s ok with us,” said Ramirez.

Goossen said contracts have not been signed but that both sides are negotiating in good faith.

“We’re having good discussions,” said Goossen. “Any fight of this magnitude is going to require a little time and care.”