The options Phil Parkinson will be considering as Sunderland are forced into defensive reshuffle

Tom Flanagan is suspended, while Arbenit Xhemajli is not expected to available after suffering a knee injury on international duty.

So who will step in?

We run you through the options that Phil Parkinson will be considering this week...

Option One: Bring in Conor McLaughlin

The Northern Irishman has not started a competitive game for Sunderland since December last year, but he did play a full part in pre-season and boosted his match fitness by playing 90 minutes for Northern Ireland on Monday night.

It was a demanding brief, too, going up against an Austrian left flank that featured Bayern Munich star David Alaba.

In a candid post-match interview, McLaughlin admitted he had been 'rusty' with so little football under his belt.

McLaughlin, though, has played on the right of the back three regularly.

He's also capable of playing left-back and so like Tom Flanagan, that role just behind Denver Hume would not be too unfamiliar.

As such, it's the option which would likely mean the least disruption to Parkinson’s preferred unit.

Option Two: Continue the O'Nien experiment

Even before Xhemajli's injury on international duty, Luke O'Nien had given his manager a dilemma.

The popular 25-year-old had been asked to fill in on the left of the back three against Carlisle United, a role entirely unfamiliar to him beforehand.

There were echoes of his first steps as a right-back in the this competition a year previous, a night that had transformed his standing as a Black Cats player.

It's not likely to be a long-term switch this time around but O'Nien took to the challenge with such ease that it may well be a role reprised this weekend.

"He was tremendous, he really was,” Parkinson said.

“In that left-sided centre-back slot, not only did he put in a faultless defensive performance, heading and clearing, but some of his ability to drive forward and support Denver was really great.

"It’s certainly given us something to think about because those two looked a real threat tonight.

“We've always had in our mind that we play with our three centre-backs, it's important that they're able to step in and join in with the play.

“The thing with Luke is that he is so good in the air as well. Carlisle are quite a big physical team, particularly when they threw the centre-half up towards the end."

Playing the role in a pressurised league game will clearly be another challenge entirely, but few would bet against this most versatile and intelligent of players making it work.

It would then man playing McLaughlin in a more orthodox right wing-back position, or giving a first league start to an exciting academy prospect...

Option Three: The youngster knocking on the door

One of the biggest issues with keeping O'Nien at centre-back is what the Black Cats lose in the wide areas.

The energy of the wing-backs is absolutely essential to Parkinson's system, particularly away from home when the defensive demands may be greater.

The win away at Oxford United earlier this season was a prime example, where O'Nien and Denver Hume wore their opponents down and became domimant in the latter stages.

The alternative, then, is to replace the irrepressible O'Nien with a similarly lively player.

Jack Diamond caught Phil Parkinson's eye on loan at Harrogate Town and impressed in pre-season, despite the fact that the 3-5-2 system might not have a natural fit for his wing play.

He is certainly raw in the defensive third, and the consistency of his end product needs work, but he has the welcome habit of always taking the positive option in possession.

That can win his team fouls and open up the pitch in the way we have seen Hume do so successfully of late.

Parkinson praised him post-match, though there were also some words of caution.

“Jack was up against a decent young player and I thought and it was a good battle," Parkinson said.

"Jack was relentless.

"Sometimes it didn’t go right for him, but other times he produced some good moments. That’s the experience and decision making you only really get from playing league football.

"We know he’s got pace and is good in one against one situations,” Parkinson said.

"He’s an exciting player and at times he showed that tonight. He probably just needed a bit more consistency in his all-round game over the course of the 90 minutes.”

Option Four: Switch formation

Parkinson, of course, did initially play with a back four after arriving on Wearside and he has an abundance of midfielders who could help make the transition a straightforward one.

Lynden Gooch and Max Power could easily help move towards a 4-2-3-1, with Josh Scowen's good recent form another factor to consider in that regard.

It would be something of a surprise, though.

Even if the formation has shifted slightly this year to accomodate a second striker, the switch to a back three marked a dramatic improvement in results and performances under Parkinson's watch and with the defensive results so impressive, it's something you suspect the Black Cats boss would be loathed to change.

Option Five: Throw in a late additon

Sunderland, of course, have until 5pm on Friday to strengthen their squad.

Thought it's a market he prefers to avoid if possible, there are potential loan additions the Black Cats boss has been tracking through the summer in case they are made available.

After that, they can still sign free agents and that may be an option Parkinson pursues.

He is still in the market for a left back to offer cover for Hume and Morgan Feeney's injury means he has also considered adding another centre-back.

Xhemajlli's setback could focus minds on that.

The question, of course, would be how match fit any arrival would be.

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