The Washington Redskins must absorb at least half of their NFL-mandated $36 million salary cap reduction this year, two people familiar with the situation said Tuesday.

That left the Redskins, with an $18 million subtraction figured in, with $12.5 million in available salary cap space listed in official records as of Tuesday morning, one of those people said, speaking on the condition of anonymity because of the sensitivity of the topic.

Without the NFL-imposed reduction, the Redskins would have had $30.5 million in available salary cap space

The Redskins must take at least half of their $36 million salary cap reduction this season but can take a larger cut if they choose, the two people said.

Team officials were discussing possible responses to the league-mandated cap subtraction, people with knowledge of the deliberations said. It was not clear whether the Redskins would challenge the reduction, either via an appeal with the league or in court.

The team had no immediate comment Tuesday about what it would do.

The NFL’s free agent market opens Tuesday at 4 p.m. It is not clear how the salary cap reduction, ordered Monday by the NFL, will affect the Redskins’ approach to signing players in free agency. But it does appear to at least complicate the Redskins’ plan to spend aggressively on the free agent market, potentially requiring the team to rework the contracts of current players to create salary cap space if needed.

The Redskins and Dallas Cowboys denied wrongdoing in the case Monday after the salary cap reductions were reported by news organizations. The Redskins had no immediate comment Tuesday on their plans.

The Redskins and Cowboys, according to people familiar with the situation, were not found to have violated salary cap rules but were given cap reductions by the league for structuring players’ contracts during the NFL’s season without a salary cap in 2010 to gain an unfair competitive advantage in future seasons. The Redskins, those people said, must absorb a $36 million reduction over the next two years, while the Cowboys must take a $10 million reduction.

“The league’s responsibility is to ensure… that every club has a fair, comparable opportunity to win, that the playing field is essentially level, and that no club starts ahead in the race to develop a competitive team,” said one person familiar with the league’s thinking in imposing the salary cap reductions. “The contracts at issue were intended to give clubs precisely such an advantage” when the salary cap system went back into effect.

This season’s NFL salary cap is $120.6 million per team. The salary cap reductions given to the Redskins and Cowboys were redistributed to 28 of the other 30 NFL teams, people familiar with the case said. That redistribution was figured into the $120.6 million cap figure for this year.