It's a day that New York Mets fans want to forget - but one that will continue to happen every July 1 for another eleven years.

Today is known in baseball circles as Bobby Bonilla Day - a day where the Mets pay $1.19million to a player who retired in 2001.

So who is Bobby Bonilla? And how exactly did he manage to still get paid all this time?

Bonilla signed with the Pittsburgh Pirates in the early 1980s and by 1986, he made his MLB debut with the Chicago White Sox.

Over the course of his career, he'd star for teams like the Pittsburgh Pirates, the New York Mets, and the Baltimore Orioles. He also won the 1997 World Series with the Florida Marlins.

He was also a six-time All-Star and had won the Silver Slugger Award three times in his career.  

But by 1999, he was on the decline in the middle of his second stint with the New York Mets. 

It was after that 1999 season where the Mets decided that they wanted nothing more to do with him and released him.

The only issue was they owed him $5.9million to pay out the rest of his contract.

But Bonilla's agent went to the Mets with an offer: they would agree to have the payment deferred for a decade and with interest, Bonilla would get paid over $1.19m per year every July 1 from 2011 to 2035.

While that meant his payout would balloon from $5.9m to $29.8m, the Mets agreed to the deal.

That's partially because Mets owner Fred Wilpon was heavily invested with Bernie Madoff in his infamous Ponzi scheme at the time.

Wilpon believed that the 10 percent returns he was making on his investments with Madoff would outweigh the eight percent interest he'd have to pay to Bonilla on the $5.9m, so he accepted the deal.

So each year, fans of baseball celebrate the payout as some sort of informal national holiday - with social media always going nuts over the deal.

One person joked, 'Too many people tweet about the Bobby Bonilla contract stuff now. It used to be a cute little cottage industry, a few mom-and-pop accounts having fun. It's gone corporate.'

Andrew Brandt, a former NFL executive and a professor at Villanova University, tweeted, 'Always amused at the reaction to Bobby Bonilla’s deferred payments. I don’t know about his interest rates, but know this: Every team, in every sport, would rather defer than pay in present. Money now better than money later. I fought with agents all the time in trying to defer.