Burnley midfielder Joey Barton has accepted a Football Association charge that he placed 1,260 bets on matches over the past 10 years.
Barton, who was charged in December, has requested a personal hearing before being sanctioned for breaking FA rules by betting on "matches or competitions" between 26 March 2006 and 13 May 2016.
It is expected Barton will offer mitigation for the breaches.
Players in England's top eight tiers are banned from betting on football.
Barton, 34, rejoined Burnley last month, having left Rangers in November.
In the same month, he was given a one-match ban for breaking Scottish Football Association rules on gambling.
Barton admitted the Scottish FA charge of placing 44 bets between 1 July and 15 September, while he was a player at Ibrox.
What are the rules on betting?
The FA brought in new rules in 2014 banning players and staff at clubs down as far as the eighth tier of the English men's football pyramid - as well as at clubs in the Women's Super League - from betting on any football match or competition anywhere in the world.
Players and staff are also prohibited from betting on football-related matters, such as player transfers, the employment of managers or team selection.
That outright ban on football-related betting applies to all involved in the game from Premier League level down to - and including - the Northern Premier, Southern and Isthmian Leagues.
Previously, participants were prohibited from betting on a match or competition in which they were involved or which could influence.
Barton has been charged with offences allegedly committed under both the new and old rules.
His Rangers contract was terminated following a training ground row which led to a falling-out with manager Mark Warburton and he played only eight games for the club.
Barton began his career at Manchester City in 2001, joined Newcastle in 2007 and then signed for QPR in 2011. He had a loan spell with Marseille in France for 12 months, before joining Burnley for the first time in August 2015.
Why has it taken 10 years to come to light?
It is understood that the FA was only made aware of the bets by the betting company prior to his second charge in December 2016, which led to its investigation.
The high number of bets has resulted in a detailed and complex investigation and the timing of the charge is not related to Barton rejoining Burnley.
He was expected to have been charged even if he had remained a free agent.