Ballard was forced off in the late stages of Saturday's home defeat to Brighton in the Premier League.
It was too early immediately after the game for Regis Le Bris to know the severity of the injury, but there'll be clarity come Friday, when Sunderland's head coach speaks to the media ahead of the game at St James' Park.
Ballard was named in the Northern Ireland squad earlier this week ahead of the crunch World Cup qualifier against Italy later this month, though boss Michael O'Neill admitted he was waiting for further information from the Black Cats.
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He said: "Our medical team will liaise with the clubs to get clarity on those situations. We don’t know the exact extend of Daniel’s injury, he came off in the 64th minute - but we’re on top of all that."
Being without Ballard for one of the biggest games of the season would obviously be a huge blow. The centre-half has adjusted to life in the Premier League so impressively and also knows exactly what this fixture means, for he's felt the agony and the ecstasy of the derby, scoring the own-goal in the FA Cup defeat at the Stadium of Light a couple of years ago but playing a key role in exacting revenge in December.
If Ballard is fit and available, he plays. But the make-up of the defence will be interesting on Sunday, regardless of what happens with Ballard.
Nordi Mukiele was expected to return to training this week, but Le Bris discussed after the Brighton defeat the balancing act and the big decision he has to make with the defender.
"Nordi is getting better, we'll see for next week," he said.
"It's always the same: you can take the risk, he might play against Newcastle, but if we lose him for eight weeks after, it doesn't make sense. We are always on the edge so we'll try to manage the situation properly."
That Sunderland have three weeks after Sunday's game before their next might prompt Le Bris to roll the dice. After all, Mukiele has been one of Sunderland's star performers this season. Only Trai Hume and Enzo Le Fee have played more outfield minutes than Mukiele.
If Ballard is unavailable, that might well make Le Bris' mind up on Mukiele. But even if Ballard gets the nod, there's a strong case to be made to bring Mukiele in at right-back, where he's arguably played his best football for Sunderland this season.
It was the Frenchman who delivered the cross that was turned into his own net by Nick Woltemade in the December fixture against Newcastle.
When Reinildo is available, he plays, so the former Atletico Madrid star is likely to go straight back in at left-back on Sunday, which, if Mukiele gets the nod, could well mean Trai Hume being used on the right side of midfield again, as he did earlier this year when Bertrand Traore had his first spell out injured.
That would be harsh on Chris Rigg, who was probably Sunderland's best player against Brighton, but Le Bris admitted last week he's likely to rotate on the right side in the absence of the experienced Traore.
Against the impressive Lewis Hall and, most likely, Harvey Barnes in front, Hume would give Sunderland an extra layer of protection down that right flank.
It then feels like the midfield three, Le Fee and Brian Brobbey up-front picks itself.
But the availability of Ballard and those defensive decisions are significant and could go a long way to deciding Sunday's game.