Magners League-winning coach Sean Holley has pinpointed Ulster as one of the biggest threats to Ospreys' aims of becoming the first side to successfully defend the title.
Holley also admits that Leinster — who his side defeated in last May's inaugural play-off final at the RDS — and Munster will also be ones to watch, along with Challenge Cup champions Cardiff Blues.
However, head coach Holley believes Ulster will need to be watched especially closely after a recruitment drive that has seen South Africa half-back Ruan Pienaar sign on at Ravenhill.
“Ulster have shown huge ambition by signing a player like Pienaar,” said Holley.
“They have brought in other players as well and will clearly be a side to be reckoned with, as will the usual suspects, Leinster and Munster, who are always there or thereabouts.
“I would expect the Blues to put in a good show too. They did well to retain Xavier Rush, have signed Dan Parks and are a side with a lot of quality.
“The great thing about last season was that the Scots came through strongly and they will be looking to build on that. There were no easy games in the league and there was doubt about who would make the play-offs until the final weekend of the regular season.
“Every side will start believing they can do something but much will depend on international windows and how teams cope when they are shorn of players — plus the fixtures that are thrown up during those periods,” he added.
The Ospreys will start the season adrift of the rest after being docked four points for a late postponement of the March 19 fixture against Ulster. An appeal is pending but isn't set to take place until after this season's campaign starts, with Glasgow taking on Leinster and Ulster entertaining the Ospreys on Friday, September 3.
“We are not thinking about that,” he said. “We're just looking forward to the start of the season.”