Olympic gold medallists Hunter and Purchase are back for the new season
Great Britain will welcome back five Olympic medallists for next year's rowing season and two-time champion Steve Williams could still return.
Tom James, who took gold with Williams, Andy Hodge and Peter Reed in Beijing, has already confirmed he will be back but Williams has yet to decide.
Both Zac Purchase, who has been ill, and Mark Hunter will return from the gold medal-winning lightweight double.
Debbie Flood and Colin Smith, who both took Beijing silver, will also be back.
In the absence of the five, Great Britain still won six medals in Olympic-class events - more than any other nation - at the 2009 World Championships in Poland.
GB team manager David Tanner has set a deadline of 28 September for those coming back to receive full support and funding.
If we're the same crew in four years' time we can't be the same speed because we won't win
Gold medallist Matt Langridge
"People that want to come back have got to want to do it and have got to be fit," said Tanner, who refused to be drawn on next year's line-ups.
"We don't need to hurry as the next World Championships [in New Zealand] are 15 months away."
Scotland's Katherine Grainger was Britain's first medallist with a silver in the women's single sculls in Poland but she is still likely to be in a larger crew by London 2012.
Grainger has won silver at three successive Olympics and has chosen to carry on until the age of 36 in the hunt for gold.
Tanner added: "I think we will want her and she will want to be in a crew boat at London but we should all have a breather [before making decisions].
"The 2010 season gives us a little more flexibility if we want to use it but we've got to be clear where we're going for 2012."
Great Britain won a single gold in Poland, from the men's four of Matt Langridge, Alex Gregory, Rich Egington and Alex Partridge.
But Langridge said the crew cannot afford to rest on their laurels as they aim to secure gold in London.
"We've got a dominant crew here and it's something I'd really like to build on but what made us good was the fact that we have to fight people," he told BBC Sport.
"If we're the same crew in four years' time we can't be the same speed because we won't win.
"Just because we've done well this year doesn't mean we will next year."
Head coach Jurgen Grobler may consider moving Hodge and Reed back into the four after they were consistently beaten by New Zealand in the pair this season.
But no decisions will be made until after a winter of trials in pairs and singles, culminating in April.
Langridge said: "The pair are Olympic champions and they don't like being beaten.
"I'm sure they're hungry to beat New Zealand but they may not get that choice.
"It's Jurgen's decision and he'll make it. We just have to make sure that the [current] four of us turn up better in April than this year."
Great Britain won silver in the men's single sculls with Alan Campbell, the men's pair with Andy Hodge and Peter Reed, and the women's double of Annabel Vernon and Anna Bebington.
In the Olympic-class events, the team also secured a bronze for lightweight double Sophie Hosking and Hester Goodsell.