Football and tennis say reversing a drop in participation will be a top priority after the sports were warned that part of their public funding is at risk.
The sports were among the worst-performing in Sport England's latest Active People Survey, which found overall that participation had recovered to the level of October 2012 of 15.5million after a slump in April.
There was good and bad news in the figures with swimming, cycling and athletics/running all putting on numbers but a worrying decline among 16 to 25 year olds.
Football is now the fourth sport in terms of participation, while Sport England said tennis has failed to capitalise on Andy Murray's success at Wimbledon.
Football's numbers are down to 1.83million, a drop of 100,000 since April, and more than 4 per cent down on the 2005 figure. Tennis, which earlier this year had a £530,000 funding cut imposed, could lose more of its £17.4million four-year award after participation fell from 423,400 in April to 406,000.
FA general secretary Alex Horne responded, saying: "These are clearly disappointing numbers. Understanding and reversing the fall in participation is an immediate and top priority and we are working exhaustively with Sport England and our other partners to ensure the right plans and programmes are in place to achieve this.
"What is clear is that the nature of football participation is changing and that our players increasingly want football on their terms; less formal, less frequent, more flexible."
Nick Humby, the chief operating officer of the Lawn Tennis Association, said he welcomed Sport England's belief that the sport was now focused on boosting participation.
Humby said: "We are of course hugely disappointed that the October 2012/13 numbers have gone down but we take encouragement from the peak between July and September exceeding that of the Olympic and Paralympics last year.
"That was partly due to Andy Murray, partly to the extraordinary weather, and partly to the stuff we are now doing out and about around Britain.
"We have been working very closely with Sport England to convert that into more people playing tennis."
Humby said there were signs of encouragement with the number of people playing monthly holding up, as has the number of women and young people aged under 16 playing the sport.
Sport England will now hold meetings with the governing bodies of football and tennis and will make a decision in January as to whether up to 20 per cent of their funding will be suspended. Football's 2013-17 funding award was £30million.
Sport England chief executive Jenni Price told Press Association Sport: "We operate a payment for results scheme, so football are definitely in the at-risk zone.
"The FA has the power to do an enormous amount of good for grassroots football as they have a lot of sponsorship, a lot of power and connections, but they need to focus and work much more effectively. They have to think big in their participation programmes."
Sport England says the figures mean the original boost of the London 2012 Olympics has been maintained and insists the overall drop in young people playing sport is almost completely down to the fall in numbers playing football and netball.
Sports minister Helen Grant said "I am encouraged that sports participation is back up on the rise compared to six months ago and that participation among disabled people is at an all-time high. More women are getting involved too and I want to keep up that momentum.
"Sports governing bodies must step up and deliver for the half a billion pounds of public money that they receive. If they don't, funding will be taken away and channelled into grassroots sport through other routes."
But shadow sports minister Clive Efford criticised the Government.
He said: "In the year following the 2012 Olympic and Paralympic Games figures show that overall participation is down. The most damning figure is the reduction in participation among 16 to 25 year olds by 51,000.
"These figures underline the fact that David Cameron has no strategic plan for sport and has failed to capitalise on the explosion of enthusiasm generated by the Olympics and Paralympics. A golden opportunity is being squandered."
There were success stories in the latest figures including cycling, with just over 2million people taking part once a week.
Swimming has halted its downturn with a 50,000 increase on April's figures to 2.93million, while athletics/running is up 63,000 to 2.01million.
Rugby league has also seen a rise in numbers - Sport England believe due to switching to become a summer sport.