Crystal Palace have agreed a deal in principle with the owner of the New Jersey Devils and Philadelphia 76ers, Josh Harris, to sell a sizeable shareholding in the Premier League club, which should mean that ambitious plans to redevelop Selhurst Park edge closer to fruition.

Harris, the co-founder of Apollo Global Management, has been seeking to invest in the English game for some time and, with his business partner David Blitzer, first entered into talks with the Palace co-chairman Steve Parish a little over a year ago.

Those negotiations stalled in the spring but contact has been revived, with the American investors’ interest in purchasing a stake in Palace as strong as ever, and there is confidence on both sides a deal will be done.

Under the offer Parish, who owns a 25% stake in Palace along with the three other members of the CPFC 2010 consortium – Stephen Browett, Jeremy Hosking and Martin Long – having bought the club out of administration five years ago, would continue to run the day-to-day operations at Selhurst Park.

Although the equal stakes held by the four owners would be diluted with Harris buying into the club, no one would have a bigger stake than Parish in shareholding terms with all parties signing up to a reinvestment programme aimed at stadium development.

The proposal is for Parish, Harris and Blitzer to have 18% stakes each and for the remaining 46% to be held by the other three co-owners.

“There are very serious conversations going on and I will remain the single largest shareholder along with David and Josh,” Parish told Sky Sports News HQ. “The day-to-day decision making control will remain the same. They will bring some fresh ideas and some fresh input which will be great.

“But I think the guys recognise that having a UK partner retains the soul of the football club which is really important and it’s important to me that my three other partners will stay involved as well. It will be a much broader investment base and everyone is signing up to a commitment to improve the stadium. So it’s an exciting time and if it comes off I think we can make some major developments for the club.”

Parish made clear in an interview with the Guardian in September that he would need at least “£80m for the things I want to do to the stadium, maybe £30m for the academy”. There is a recognition that Palace need a new main stand and will have to make significant improvements to the Arthur Wait stand opposite, with progress having been made with architects on a phased scheme that would expand the capacity of Selhurst Park, the club’s home of 91 years, to 40,000.

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Although there are planning obstacles to overcome, there has also been initial and positive dialogue with Croydon and Bromley councils, with any scheme to seek to regenerate that corner of south London.

Retention of Premier League status would allow the current owners to achieve such redevelopment incrementally over the long term, but Parish has admitted to being “a bit more impatient than I was when I was 20”, with the need for further investment therefore obvious. “We’d need the right investment, but with the right governance so that I can still make the decisions I need to make,” he said in September.

He and his fellow owners have built up a solid relationship with Harris and Blitzer over the past 15 months, with the Americans having apparently bought into the ethos promoted at Palace, who have tapped into the club’s community roots in south London. All parties are confident the joint local and American ownership model represents the best choice for the future.

A deal could be announced before Christmas if, as anticipated, negotiations are concluded smoothly in the coming weeks. Harris, who has an estimated worth of $2.1bn, and Blitzer added the National Hockey League’s New Jersey Devils and their arena, the Prudential Centre in Newark, to their portfolio in 2013.

The private equity investor has watched Palace establish themselves in the Premier League over the past two seasons, with 11th- and 10th-place finishes, after two decades spent largely in the second tier. Alan Pardew’s team are eighth after Sunday’s 2-1 victory at Liverpool.