Lance Armstrong’s admission to Oprah Winfrey in January, 2013, could end up being quite costly to the disgraced cyclist. (George Burns/Associated Press)

A federal whistle-blower case lawsuit against Lance Armstrong and several key associates will proceed largely intact, in light of an 81-page ruling issued Thursday by a federal judge.

U.S. District Judge Robert L. Wilkins declined to dismiss the crux of the government’s argument in the complex fraud case initially filed in 2010 by former Armstrong teammate Floyd Landis. Last year, U.S. Justice Department joined the case, which seeks repayment and restitution for the roughly $40 million that the U.S. Postal Service paid to sponsor Armstrong’s team from 1998 to 2004 — a period in which he has acknowledged using banned substances and blood doping to enhance his performance, in violation of his contract.

If found guilty of defrauding the government, Armstrong could be fined three times that amount. He already has been stripped of his seven Tour de France titles.

Wilkins’s ruling dismissed certain claims against Thomas Weisel, an investor in the cycling team, but allowed other claims of fraud and breach of contract to stand against Armstrong, former team manager Johan Bruyneel and Tailwind Sports. The ruling did not address the merits of the government’s case; rather, it allows it to proceed to the next legal step.