It is, without question, a gamble.
Sunderland are delivering a full-back who can be a destructive attacking force into the arms of a direct relegation rival.
Not only that, but to a manager who oversaw a dramatic improvement in his game last season.
One of van Aanholt’s first games will be a six-pointer with his former club at the beginning of February, and it would be no surprise to anyone if he came back to haunt the Black Cats painfully quickly.
Yet no one could be under any illusion that van Aanholt was a player who was going to save Sunderland from the drop this season.
His final performance, the 2-0 defeat at Hawthorns last weekend, was a sour note on which to end his Wearside association.
Deployed in a wing-back role that should have suited his game, van Aanholt showed little to no interest in playing his part in what was a key battle, Matt Phillips coasting down the right flank with little resistance.
My mind was cast back to Graeme Souness’ Liverpool team-mates telling tales of what made the Scot such an oustanding team player. Whenever a player was out of form, low on confidence, Souness would never be more than five yards from them at the start of a game, showing for the ball, doubling up in the tackle, covering for any potential mistake.
Well, with O’Shea and Djilobodji struggling against Phillips and looking exposed, van Aanholt largely left them to it.
It was a performance that seemed to make clear that this was not his fight anymore.
Sunderland fans are quite rightly pointing out that what really matters is what the club do with this money.
If a loan replacement is found for the 26-year-old, can the money help bolster other, ailing areas of the squad? Can they land the target man who can knit together the attacking play, or a creative midfielder who can make things happen on the ball?
If so, van Aanholt’s unquestionable speed and attacking appetite will not be quite so badly missed.
If not, this will give the impression of a club cutting costs and bracing themselves for a brutal relegation.
Worth pointing out, too, that van Aanholt’s Sunderland progression is the kind of business many have been crying out for the club to follow for years.
Identified as a young player with big potential and at a bargain price, Sunderland have turned him into an experienced Premier League operator who has made them a major profit.
That has to be the model from the summer onwards, regardless of what league the Black Cats find themselves in.
It may well be that van Aanholt goes on to blossom under Big Sam, leaving Sunderland wondering what they have done.
Ultimately, however, it is £14 million for a defender who had little appetite for defending in a relegation scrap.