Exeter City Football Club is challenging the Nationwide Conference in the High Court in a dispute over the club's financial problems.
Exeter City reached agreement with the majority of creditors in October
The club fears one of the league's rules leaves it open to a legal challenge from the Inland Revenue which could ultimately force it to close.
The club had hoped a deal agreed with the majority of its creditors over debts of about £4m had saved it from going under.
But the Inland Revenue, which is among the creditors and is owed about £350,000, is going to court to challenge the agreement.
In October, club representatives met creditors and thrashed out a Corporate Voluntary Arrangement (CVA), under which those owed money will receive 10p in the pound, to be paid off over the next five years.
But there is a strict rule, enforced by the Nationwide Conference, forcing any club that goes into a CVA to pay its football creditors, such as the players, in full.
The rule stipulates that clubs which do not comply will be expelled from the league.
But the Inland Revenue is challenging the CVA because it believes the football creditors' part of the agreement is unlawful.
Fans gained control of the club early in September when the Exeter City Supporters' Trust took over the majority shareholding of former club chairman Ivor Doble for an undisclosed fee.
The club was relegated from Division Three at the end of last season into the Nationwide Conference, where they are currently enjoying a successful season.