The curious case of Declan John's Sunderland loan so far and why he could still prove to be key

To know whether Sunderland have played well, you only have to look at Denver Hume’s heatmap.

If Phil Parkinson’s system is functioning as it should, Hume will be essentially playing as a winger.

He will get plenty of touches just past the halfway line, allowing him to drive infield and carry the ball through the opposition midfield.

There will be plenty further up the pitch, too, where Hume’s overlapping runs allow him to fire in the low crosses that Parkinson believes to be absolutely essential to his side’s attacking success.

If Sunderland have played poorly, particularly at home as they did in the first halves against Doncaster Rovers and Ipswich Town, then he will be left largely marooned in the middle of his own half.

It prevents his side playing with width, in turn leaving the centre-forward isolated and too dependent on winning ‘fight balls’ fired upfield from deep.

Getting Hume up the pitch means Sunderland have control of the midfield, allowing their centre-halves to get right up to the halfway line. This way, they can maintain a tempo to their play and ‘lock in’ their attacks.

Supporters have taken great heart in seeing this more aggressive, dynamic playing style take hold since the start of the year.

Equally heartening is to see an academy graduate at the very heart of it, justifying the faith Jack Ross showed in making him his first-choice left-back ahead of the new season.

It has been far from plain sailing, and the change in shape has been crucial because Hume invariably has a proven centre-half now tucking in right behind him, giving him the assurance he needs to push forward and reducing the dangerous situations where he is left 1-v-1 with a winger near his own byline.

His game is developing, his positioning improving and that was never summed up than his part in the mightily effective and important rearguard at Oxford United.

Hume is a player flourishing, and though there are elements of his game that can of course still be improved, that is to be expected from a player still essentially in his first full season of senior football.

The point is that Hume is that Parkinson is not a manager who likes to rotate and in this kind of groove, Hume is not going anywhere soon.

All of which leaves Swansea City loanee Declan John in something a bind.

John arrived on deadline day eager for gametime after falling well down the pecking order in South Wales.

So far, he has yet to make a matchday squad.

Parkinson went out of his way after the 3-0 win over Bristol Rovers to praise the Welshman for both the application and quality he has shown behind the scenes since arriving on Wearside.

“Declan has been training well, and more importantly he has been great in and around the boys,” he said.

“Obviously you come to a new club and you want your opportunity, but if it comes he'll be ready.”

John’s arrival on Wearside had raised eyebrows just a touch, precisely because it was clear that this was a scenario that could develop.

Heading into the final stretches of the window, Parkinson regularly alluded to the face that a left wing-back was the most important bit of business he would do.

The departure of Laurens De Bock meant Hume was his only orthodox option in that role, leaving him one injury or suspension away from having to make major changes to a system and structure that was beginning to produce results and performances with impressive regularity.

Yet conversely, this meant it was also the signing he in some ways most feared not being able to secure a good resolution.

Any player coming to Sunderland would know exactly where they stood in the pecking order, at least initially.

For a potential loanee desperate to play, it didn’t seem like the best fit.

So to land a player of John’s standing was a significant boost.

Granted, John may not quite have hit the heights expected when he broke through at Cardiff City in the Premier League back in 2013, but he still has plenty of experience and has played most of his career at a higher level than where he finds himself now.

A sign of the quality he undoubtedly possesses was underlined when Ryan Giggs brought him straight back into the Wales fold after being appointed in 2018.

He’s a player with the potential to succeed at this level, and himself admitted that he thinks this system would be a perfect platform for his attacking style.

That he can’t find his way onto the bench in a surprise, but there is a logic to it.

At the moment Parkinson is favouring Conor McLaughlin, because the Northern Ireland international has the added versatility of being able to slot into the right of the back three.

Luke O’Nien can switch over to the left if needs be, and if Parkinson is in search of extra attacking firepower in a game, he also has the option of dropping Lynden Gooch deeper and bringing on an extra forward that way.

With Duncan Watmore, Antoine Semenyo and Kyle Lafferty all pushing for more action, he has plenty of options.

It leaves John in a curious place ahead of the run-in.

As it stands, it is not entirely beyond the realms of possibility that the 24-year-old will return to his parent club in the summer having barely featured.

It’s also equally possible that at just about any stage, he could instantly become an absolutely pivotal figure in Sunderland’s bid to get back into the Championship.

He is one of a handful of players in a similar position at the moment, and one of Parkinson’s biggest tests is to manage that situation.

The path to regular action for John, and indeed Semenyo or Josh Scowen, looks a long one at the moment.

Yet the injury to Bailey Wright showed how quickly that can change, and so a defining role cannot yet be ruled out for this talented left-back.

Key for John will also be to demonstrate his attacking prowess on the training pitch, so that even if Hume maintains his form, the Welshman can be seen in Parkinson's eyes as a genuinely game-changing option in the final third.

Parkinson insists he will be ready for that chance if it comes.