The number of County Championship matches teams play in a season could be cut from 14 to 10 with a First Division of six teams, under proposals from the England and Wales Cricket Board (ECB).
The ECB's high-performance review also suggests dedicated windows for the One-Day Cup, T20 Blast and the Hundred.
The review - led by Sir Andrew Strauss - is aimed at improving the success of the England men's team.
"We must be open-minded to change," said former England captain Strauss.
The ECB hopes the revised schedule will allow a greater balance between red and white-ball cricket, produce higher quality matches, ease the strain on players' workloads and better compete with franchise Twenty20 competitions such as the Indian Premier League.
Under the proposals:
- The start of the County Championship would move from April to May and run continuously throughout the summer months - rather than being split between the start and end of the summer as it is currently - and finish in September, with teams playing a minimum of 10 games.
- There would be two second division conferences of six teams, with one promotion place decided by an end-of-season play-off.
- The One-Day Cup would take place in a single block in April and could include minor counties in an FA Cup-style knockout format.
- The T20 Blast would reduce from 14 matches to 10 and would also be in a single block from the end of May to end of July.
- The Hundred would be the only white-ball competition to take place in August, with 'first-class cricket festivals' offering specialist red-ball players not competing in that competition the chance to play extra matches.
Any changes to the domestic structure have to be agreed by two-thirds of the 18 first-class counties. The ECB hopes to have a final decision by November with an intention to implement the changes in time for the 2024 season.
Essex chief executive and interim chair John Stephenson told BBC Essex that as it currently stands, the club would not vote in favour of any reduction in the Championship.
Strauss, a former ECB director of cricket, says the proposals will not please everyone, particularly smaller counties who may fear a loss in revenue, but is confident of reaching an agreement for the greater good of the game.
"It is impossible to keep everyone absolutely content," he told BBC sports editor Dan Roan.
"But what I would say is we have heard universally that the status quo is suboptimal. People want a different solution and that is what we have provided.
"I'm hopeful that the game is going to come together and see the advantages. My job is to talk to a lot of county chairmen over the coming days and weeks and hopefully move things forward."
Why has the ECB proposed these changes?
The ECB cricket committee commissioned the review after England's disastrous Ashes tour of Australia last winter.
It aims to produce an England side that is the world's best team across all formats within five years - defined as being number one in at least one format and in the top three of the others.
"Historically our performance at international level has been below what we would like," Strauss said. "We want to be the best team in the world, across all formats sustainably, we've never really done that.
"The game of cricket is moving very quickly around these tectonic plates everyone keeps talking about - the rise of domestic franchise tournaments around the world. Our players have never had more opportunities outside the international game. We need to be cognizant and recognise that to make sure we're able to both provide opportunities and financial reward for our players to keep involved with English cricket and keep playing international cricket.
"The third issue is around the domestic game, which is such an important part of this. This is the breeding ground of our next England players and it's obviously hugely important to a lot of people."
The report concluded that the average first-class county plays 79 days of cricket during the season, more than any other leading cricket nation. That equates to the average team playing on 45% of days during the season, compared with 31% for players in other leading Test-playing nations.
England Test captain Ben Stokes is one of the most high-profile players to
voice concerns about the schedule and cited it as one of the reasons why he
retired from one-day internationals earlier this year, though he also told the
Telegraph last month that reducing the number of County Championships games was "not the answer".
Under the proposals there would be a 15% reduction in the total volume of cricket played, with the average county playing 11 days fewer.
ECB central contracts would also be adjusted to ease player workloads, particularly for fast bowlers and multi-format players, in response to increasing competition from franchise cricket.
What else has the ECB review recommended?
In total there are 17 recommendations, all of which have been endorsed by the ECB and executive. It plans to implement 15 of the 17 recommendations within its remit, with the other two relating to the domestic schedule subject to approval by the counties.
As well as the schedule, the recommendations are designed to address a number of other concerns with the English game.
Among the proposals is the trial use of the Kookaburra ball in County Championship matches. Cricket in England is usually played with a ball manufactured by Dukes, which tends to move more and for longer, suiting seam bowlers.
The ECB hopes the use of the Kookaburra ball, which is often used abroad and tends to move less, would test seam bowlers' skills more. It could also encourage captains to give more opportunities for spin bowlers, who currently bowl just 22% of overs in England - the lowest of any domestic system.
Other recommendations include:
- A North v South game played overseas to give players more experience of playing red ball cricket outside England.
- The formation of a 'Performance Advisory Group' consisting of experts from outside of cricket.
- An increase in the diversity of people in high-performance roles.
- A County Championship bonus points system to encourage positive cricket and incentivise higher quality pitches.
- A rebalance the England Lions schedule to an 80/20 focus on red ball v 50-over cricket, with no T20 cricket.