The Monopolies and Mergers Commission, which is preparing a report on the takeover, has written to BSkyB and Manchester United with a suggestion that the broadcaster does not buy rights to matches that it does not intend to broadcast.
The clause is one of a number which the MMC is thinking of insisting upon in return for waving through the BSkyB-Manchester United takeover. The watchdog is due to deliver its report to Stephen Byers, the Trade and Industry Secretary, by March 12.
At the same time, industry experts believe the clause could provide the basis for a compromise in the dispute between the Office of Fair Trading and the Premier League, which is currently being heard in front of the Restrictive Practices Court.
The OFT, which accuses the Premier League of behaving as a cartel, wants to increase the amount of live football on television.
BSkyB's current contract with the Premier League allows it to broadcast 60 live matches a season. Because the arrangement is exclusive, the other 320 matches are not shown.
If the MMC insists on the condition, BSkyB would either have to expand massively its coverage of Premier League matches or agree to allow other broadcasters to televise matches. City analysts said that, with the explosion in the number of channels as a result of digital television, BSkyB could increase its coverage.
However, lawyers for BSkyB are resisting the condition by arguing that it would make it almost impossible to put a value on the contract. At the moment, BSkyB chooses the matches it wants to show several months in advance.
The Premier League is also resisting the move. It argues that increasing the number of games on television would cause fixture chaos. Uefa, the body that oversees European football, prevents Premier League matches from being televised at the same time as matches in other leagues are being played. As a result, television matches would have to be moved from Saturday afternoon.