It hasn't been confirmed yet of course; but Patrick van Aanholt's move from the Stadium of Light to Selhurst Park would, ordinarily, be a bad thing. The loss of one of your better players to a relegation rival can surely never be a good thing - can it?
Well, yes - yes it can; and here's three significant reasons why this deal is a positive one for a club which needs a boost right now.
1. The Freeing Up of Oodles Of Available Wages
Sunderland have had it up to here for some time now - maxed-out on their allowable available salary expenditure due to Financial Fair Play (FFP) regulations. When your player wage bill is something like 76% of your turnover, you really do have a problem.
And that's why the FFP regulations exist - to stop clubs like ours going beyond the usual boundaries of sense into a realm of insanity by spending what they can't afford. Though in Sunderland's case, the effectiveness of even that principle contained within the regulations is dubious.
The painfully slow progress made in this transfer window is in part due to the inability of the club to sign anyone because we can't pay them; and sportsmen are a funny bunch - most won't sign on for free.
Patrick van Aanholt is thought to have earned circa £50k-£60k a week since he signed a four-year contract extension last summer. So that's a chunk of wages freed up right there. But FFP is a lot more complex than that and the impact on the wage bill is bigger than just a straight swap.
This smile says enough! Very happy to be part of the #SAFC family, I feel at home here! @SunderlandAFC pic.twitter.com/Wy8lVLXRal— Patrick van Aanholt (@pvanaanholt) June 8, 2016
To arrive at a true figure which Sunderland can now pay a replacement - or replacements - an enormous calculation is required to adjust the state of the finances and permitted expenditure. If you can't be bothered to mess with your head over figures - like us - skip the next paragraph.
First the multiple involves taking the profit on this first deal of the mid-season window; deduct van Aanholt's wages; factor in the losses on players in the summer and the impact that their wages coming off the bill has had; add back in various deals for current playing staff which were renegotiated at the same time; and chuck in some other stuff that only financial people understand - so we got someone else to do it.
And they arrived at a decent enough but ball-park estimate that Sunderland now have £100,000 per week freed up in the wage bill. Enough for another Jermain Defoe - with a little change to spare.
2. A healthy profit - The fourth in forty-seven, the start of better business?
Patrick van Aanholt will head an elite club once his sale is confirmed. The Dutchman will become Sunderland's fourth player in recent years to turn a profit on his departure, and he will take his place at the head of the hall of infamy at the Stadium of Light which contains the last forty-seven footballers sold.
James McClean, Simon Mignolet and Darren Bent are the trio who previously headed up the now widely circulated list of those players paid for from elsewhere and then sold on by Sunderland for more than what was originally shelled out for them.
And van Aanholt becomes the one to top the list if we accept a final figure of £14m to be paid by Palace - and then knock off 30% for Chelsea's sell-on clause - and equate it to the £1.6m originally paid when Sunderland bought him in 2014. A profit of £8.2m.
Compare that with a gain of £1.25m for McClean, £2m for Bent and £5m for Mignolet, and suddenly the piece of business looks starkly successful for a club which has hemorrhaged money on 99% of the players it has bought in recent years.
When Chief Executive, Martin Bain, discussed Sunderland's dismal financial situation at the end of last year, he made a point of repeatedly emphasising the need for the club to become smarter at player-trading. For a club of this size, selling on players for a profit is the only way by which to become sustainable.
Does the van Aanholt sale represent a step in that direction at last? Or is the sale of the Dutchman merely representative of the current state of the Premier League transfer market and a culmination of the effects of giving Sam Allardyce a pot of money to fix a relegation-threatened defence at Crystal Palace?
3. The Footballing Benefits
There are several footballing reasons why van Aanholt leaving for Crystal Palace is not a good thing. His ability to dance into an opponent's penalty area for one, coupled with his injection of pace in an otherwise pedestrian squad, not to mention a few goals a season; but there as many reasons to believe that signing an upgraded left-back will be a cause for optimism.
The position of left-back had been a problem one at Sunderland for years before the arrival of van Aanholt from Chelsea. At one time, any player who could kick a ball with their left foot was bunged in at full-back - or so it seemed.
The Dutchman made the position his own and Sunderland have never had much cover for him or competition for the shirt. In essence, van Aanholt has always been undroppable - even in the pits of his sometime abysmal spells.
The problem with selling him to a relegation rival of course rests on whether Sam Allardyce can get the best out of him - like he did for ten games last season. Sadly, for a club in Sunderland's constant turmoil, a run of ten decent games in two-and-a-half seasons isn't what's needed. David Moyes has a squad of players like that - which is why his side are where they are in the league.
With a bit of cunning, some decent scouting and a hefty dose of luck, Moyes and his new 'Chief Football Officer', Simon Wilson, might even unearth a left-back who doesn't turn his back on his opponent regularly; often lose his man when defending set-pieces; get beaten on his inside or outside depending which may the wind is blowing; or take the huff when things aren't going so well.