Super Rugby's three expansion sides have performed as well as expected this season as they struggle to adapt to regular travel requirements and the higher intensity of games, according to southern hemisphere rugby's boss Andy Marinos.
The competition was expanded to 18 teams this season with the return of the Kings in South Africa and new entries from Japan (Sunwolves) and Argentina (Jaguares).
With the competition at the halfway stage, all three teams have won only one game each and some of their performances have caused concern that the tournament has expanded too quickly and the new teams lack depth.
"History has shown any new team coming into this competition struggles," SANZAAR chief executive Marinos told reporters on a conference call from Cape Town.
"As much as it's a battle of attrition on the field, the mental fatigue is also pretty significant and that takes time for athletes who haven't been used to it to adapt to the rigours of getting up every single weekend."
The Sunwolves shook off a 92-17 mauling by the Cheetahs two weeks ago to beat Argentina's Jaguares 36-28 last Saturday at Prince Chichibu Stadium.
Crowds have been between 15,000 and 20,000 in Tokyo, while the Jaguares are attracting similar numbers in Buenos Aires, which is "unbelievably good", Marinos said.
"The new teams have added something different. The broadcast reach is also growing ... and that has increased the attractiveness and reach of our product into markets we had not penetrated or had much impact in the past," he added.
One of the concerns was the viewing figures within the traditional markets, which were flat or in decline.
"There was a time when some viewers watched all the games but viewing has become more tribal in terms of following your team," Marinos said. "Obviously, performances on the field are linked to viewing numbers, too."
While the draw had been engineered to lessen some of the travel demands on players it was too early to overhaul the competition, he said.
Administrators would talk to all of the teams, coaches, broadcasters and national unions to discuss their concerns in a strategic overview at the end of the season though they would not make any changes, if any, until the 2018 campaign.
"My view is that we need to give the competition time to bed down," he said.
"(But) if we find ourselves faced with a proposition that is a lot more valuable, maybe we look at a change in the competition, either expanding it, or manipulating the current model that we've got to try and get a different balance or different outcome."