Cardiff Blues say they cannot put their 2014/15 season tickets on sale yet because of uncertainty over rugby's future.
The Blues claim they were expecting to make £25,000 after the tickets went on sale on 1 February.
But disputes at home and abroad mean elite level teams do not know which competitions they will be in next season.
"We cannot go on sale," said Blues Chief Executive Richard Holland.
"From a commercial side of the business it would be unreasonable of us to ask our supporters to buy season tickets for something they don't know is going to exist.
"We would usually go on sale for our season tickets on the 1 February, which would usually deliver about £25,000 of cash flow into the business.
"We cannot do that. We cannot give certainty to our sponsors and we cannot give certainty to the players.
"There is a lot of uncertainty and that is why we need clarity."
This is set against the background of a wider dispute over the future of European rugby, with a rival European competition to the Heineken Cup - the Rugby Champions Cup - on the table and the possibility of the Blues, Newport Gwent Dragons, Ospreys and Scarlets also playing in an Anglo-Welsh competition instead of the Pro12.
Holland says the situation has led to the decision to put season ticket sales on hold.
"We need a decision made on the competitions that we are going to be playing in," said Holland.
"The regions have submitted a proposal for ourselves to play in the Rugby Champions Cup next year, and we have put that to the Welsh Rugby Union.
"We are waiting for a response from them before deciding on our next move."
The BBC has asked the WRU for a response and the other three regions what their season ticket plans are.
The governing body has presented the regions with a detailed legal contract called the Rugby Services Agreement, but competitions appear to be a major sticking point with the WRU insisting on support for the present tournaments and associated television contracts.