Promotion and relegation between the top tiers of English rugby will continue for the foreseeable future, the head of Premiership Rugby says.
There were discussions in 2015 over creating a ring-fenced 14-team league, but this plan has now been shelved.
"What is most important for us is the energy within the league," Premiership Rugby chief executive Mark McCafferty told BBC 5 live.
"For the next few years, within our current agreement, that is the case."
Bristol's relegation to the Championship next season has already been confirmed, although they will be given a reprieve if either Ealing or Doncaster win promotion.
"Bristol is a big city, a big rugby club with lots of heritage, and they are investing for the long-term," McCafferty added.
"So I don't think it will be very long before we see them back in the Premiership.
"But we have to be very careful we do generate [that energy], and there are examples of leagues around the world in rugby where there isn't relegation, and it can become a little bit predictable at the bottom end of the table.
"No relegation wouldn't have seen growth of the likes of Exeter particularly and Worcester as well. So we have to try and strike that balance."
Meanwhile London Irish and Yorkshire Carnegie have met the Minimum Standards Criteria and will go up to the Premiership if they win the Championship play-offs.
However, with only two clubs in the second-tier capable of promotion, McCafferty acknowledges the need to grow the Championship on and off the field.
"I think the gap is getting bigger commercially. On the field there is probably not as big a gap as there is off the field," he added.
"Finding the right structure for the Championship is quite important, and we have to work with the RFU and the Championship on that.
"We can't ignore that level of the professional sport, because it is very important within the whole system."