For a player whose infectious character and eye for goal brightened up The Hawthorns like a rainbow after the downpour of the previous season, the reasons behind his fleeting stay are cruelly black and white.
Albion cannot afford his wages. His contract, believed to be worth £55,000-a-week, is a Premier League one.
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Sign him permanently from Newcastle and he could naturally expect that to increase to at least £60,000-a-week. Across the next three years.
The Baggies stretched themselves as far as possible this season. Their wage bill of £38million was one of the highest in the division, nearly double the estimated average, and a huge chunk of their turnover.
That was cut from £83m the season before, but it will have to be trimmed even further this summer.
It is not necessarily next season that would be the biggest problem in buying Gayle, when Albion will once again receive £40m from the Premier League in their second year of parachute payments.
But the season after that when they get just £9m, and the season after that when they get nothing at all.
Thanks to an owner unwilling to invest, Albion have essentially got £49m plus what they make from player sales to keep them competitive over the next few years. They can no longer hand out big contracts – regardless of who they are for.
Last season, Gayle's salary was just £1m shy of Rotherham's whole playing budget. That is unsustainable in this division without a benefactor at the top dipping into deep pockets.
The counter-argument is that the Newcastle loanee is a special case, gambling with him is no gamble at all.
Nobody guarantees you around 25 goals a season in the Championship like he does and selling Salomon Rondon for his £16.5m release clause banks a large chunk of Gayle’s hypothetical £10m fee and three-year contract worth £9m.
How can the board fail to capitalise on the relationship he’s built up with the club over the past 12 months? Surely he would fire the Baggies to promotion next season?
But Albion had two strikers who scored more than 20 goals this season and still they didn’t go up. In some ways, they were fortunate neither fell injured.
For lessons in how not to run a football club in the second year of parachute payments, Albion need to look no further than four miles down the road.
Villa were in a desperate state last summer before Wes Edens and Nassef Sawiris saved them.
Tony Xia gambled the house on promotion with big contracts on players, and losing at Wembley last summer nearly left them in administration.
Money from selling Rondon needs to be used to help rejuvenate other areas of the squad too – it can’t all be spent on one player.
Albion need to make several signings this summer with the funds generated by a few sales.
Six loanees have already left, and Gareth Barry and James Morrison have all-but gone too. That’s eight players who already need replacing with no money gained from their departures.
Despite this, for many fans, this Gayle news represents something far more depressing.
All supporters love strikers, especially ones like him who put the ball in the net on a regular basis with a smile on their face.
Not signing him is symptomatic of an ownership model that appears to be gearing up for the first stage of a managed decline into mediocrity.
Regardless of the financial truths, it is the sort of cold hard business decision that slowly erodes the love of the game.
It’s a damning indictment on the disparity between the Premier League and the Championship, but also a worrying forewarning of what’s to come under Guochuan Lai.
If Albion can’t afford to sign Gayle, after the season he’s just had at The Hawthorns, then what’s the point of it all?
The board’s argument is that these are exactly the sort of difficult decisions that need to be made to ensure there is still a West Bromwich Albion to support in years to come.
But merely surviving shouldn't be the extent of a football club's ambition.
Chief executive Mark Jenkins and technical director Luke Dowling bore the brunt of the criticism after this announcement, but they have their hands tied by an owner determined to keep the club self-sufficient.
Jenkins inherited a mess on his return after the previous incumbents splurged £40m worth of reserves painstakingly built up over years of shrewd recruitment and Premier League existence.
He can’t afford to make the same mistakes John Williams and Martin Goodman did and it's infuriating that some of those mistakes are still hoovering up a budget that leaves no room for Gayle.
The lovable striker won’t be the only victim of this new financial model this summer. But he is by far the most high-profile.
It was Dowling who delivered the news, and although he was refreshingly candid, it was also pretty stark.
“We don’t want to keep players on big contracts and have to lay the general staff off and make people redundant,” said the technical director.
“If it means two, three, four, or five players move on, then they move on. We have to back ourselves to replace them.”
This model puts a lot of pressure on Dowling’s summer. Not only does the technical director have to find the right head coach, now he has to replace Gayle too.
With Rondon also leaving and Jay Rodriguez expected to follow, it's highly likely the Baggies will need to buy three strikers this summer.
That's before you get to the wholesale surgery desperately needed in midfield and the potential interest in two or three of Albion's defenders.
The Baggies will still have a competitive wage bill next season, expected to be above the £20m average in the division. But there's no doubt Dowling has a daunting summer ahead.
Encouragingly, he sees it as an opportunity rather than a hindrance, but it will be his first big test.
Get it right, and he’ll be heralded a magician. Get it wrong, and Albion could be left in the wilderness for several years to come.
The Baggies are facing a huge rebuild, but the enormity of it is only now starting to hit home.