Burnley midfielder Joey Barton has been banned from football for 18 months after admitting a Football Association charge in relation to betting.
The 34-year-old has been fined £30,000 and warned about his future conduct after being charged with breaking FA rules for placing 1,260 bets on matches between 26 March 2006 and 13 May 2016.
Barton said he is addicted to gambling.
He plans to appeal against the length of the suspension, calling it "excessive".
"I have fought addiction to gambling and provided the FA with a medical report about my problem - I'm disappointed it wasn't taken into proper consideration," he said.
The midfielder bet on some matches in which he played but he stressed in a statement on his website that "this is not match fixing" and that at "no point in any of this is my integrity in question".
He added: "I accept that I broke the rules governing professional footballers, but I do feel the penalty is heavier than it might be for other less controversial players.
"The decision effectively forces me into an early retirement."
Later on Wednesday, Barton tweeted: "Thanks for the many messages of support. I have breached FA rules. I have been honest with the reasons. Many agree the punishment is OTT."
- 'I'm addicted to gambling' - Barton's statement in full
- Flawed & controversial - the complex career of Joey Barton
- Gambling companies prey on 'vulnerable' footballers
- 53 footballers reported over potential breaches of betting rule
The PFA echoed those sentiments, saying that "sanctions for breaches must always be proportionate".
In a statement, they added: "We hope sufficient weight is given to the sanctions handed down in other cases of a similar nature."
Barton also called on the FA to do more to tackle the culture of gambling in football.
He added: "If the FA is truly serious about tackling the culture of gambling in football, it needs to look at its own dependence on the gambling companies, their role in football and in sports broadcasting, rather than just blaming the players who place a bet."
Players in England's top eight tiers are banned from betting on football but Ladbrokes is an FA partner and 10 Premier League clubs have betting firms as shirt sponsors.
The former Manchester City and Newcastle player rejoined Burnley in January, having left Scottish Premiership side 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 2016, while he was a player at Ibrox.
'I bet on my own team to lose'
Barton said that since 2004, on an account with Betfair, he placed "over 15,000 bets across a whole range of sports" - of which 1,260 were on football - staking an average of £150 per bet.
Between 2004 and 2011 Barton said that he also placed several bets on his own team to lose matches but added he was not involved in the match-day squad in any of those instances.
"I had no more ability to influence the outcome than had I been betting on darts, snooker, or a cricket match in the West Indies," said Barton.
"On some of those occasions, my placing of the bet on my own team to lose was an expression of my anger and frustration at not being picked or being unable to play.
"I have never placed a bet against my own team when in a position to influence the game, and I am pleased that in all of the interviews with the FA, and at the hearing, my integrity on that point has never been in question."
Barton's bets on matches he started include a £3 stake on himself to be first goalscorer for Manchester City against Fulham in a Premier League game in April 2006. Then City team-mate Richard Dunne scored the first goal in a 2-1 defeat.
Barton betting timeline
- 24 May 2016: Joins Rangers from Burnley on a two-year deal
- 19 September 2016: Banned for six weeks for a training ground altercation
- 20 September 2016: Investigated by Scottish FA over breach of betting rules
- 10 November 2016: Barton and Rangers agree to terminate his contract
- 17 November 2016 : Given a one-match suspension for breaking Scottish FA rules on gambling
- 20 December 2016: Rejoins Burnley on a short-term contract
- 3 February 2017: Accepts a FA charge that he placed 1,260 bets on matches over the past 10 years
- 26 April 2017: Banned for 18 months
Why did it take 10 years to come to light?
It is understood that the FA was only made aware of the bets by the betting company 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 was not related to Barton rejoining Burnley.
He was expected to have been charged even if he had remained a free agent.
Barton began his career at Manchester City in 2001, joined Newcastle six years later 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.
What are the rules on betting?
The FA brought in new rules in 2014 banning players and staff at clubs down to 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 they could influence.
Barton was 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.