Where Cats stand in transfer market
The EFL’s salary cap is continuing to complicate Sunderland's search for January reinforcements.
Head coach Lee Johnson remains keen on strengthening his squad this month, after making Carl Winchester his first signing last week.
The Black Cats boss is eager to add another attacking option, while a serious injury to Denver Hume means that he is also now keen to find additional cover at left-back.
Sunderland's key issue is that they are operating close to the salary cap limit, both in terms of the size of the squad and their wage spending.
Johnson's dialogue with senior figures at the club have left him with the belief that there is a small amount of 'wriggle room' for him to operate within, but it is very limited.
One of the key issues is that the complicated rules mean moving out players does not necessarily allow clubs to spend the same amount on another player.
To allow clubs to transition to the new rules, players who signed contracts before the rules came into place are currently being calculated according to a League One average.
It means all deals this month will be subject to complex calculation, and it's also causing issues when it comes to negotiating with potential targets.
Johnson said last week that some potential scenarios Sunderland had drawn up for rebalancing the squad had
turned out to be impossible due to the complex rules.
"It's very strange but one player could go out, let's player A, and you could get nothing in return in terms of the salary cap," Johnson said.
"Player B could go out and you could get his maximum wage back in terms of the cap.
"It doesn't make sense really in terms of the logic of it but there is method to the madness
behind the scenes.
"It' s one of those where players probably don't understand it, the media probably doesn't understand it, and a lot of agents definitely don't understand it.
"That is providing us some difficulty at the moment!
"Even internally, we have to work really hard to try and find some wriggle room within that."
The completion of Kyril Louis-Dreyf us' take over will do little to solve the above issues, though it of course could give Johnson greater scope in terms of transfer fees, which are not subject to the cap.
Players under the age of 21 are also exempt, leaving loans as a serious option for the club as it stands.
Johnson's mantra is to ensure any signing meets his criteria: "Affordable, accessible, available and match fit."
He is eager not to leave the squad too big, or block the development of any homegrown player.
Which explains why for now, he is holding his nerve and waiting on the players who he believes could make a genuinely instant impact.
"[There's] not an awful lot [happening] to be honest.
"I think that we're positioned so that it could change very quickly. What we've got to be really considerate of is getting value.
"I think too many times in the past the club has probably chased it, if you like, and made snap decisions that they've got wrong.
"So we're trying to be really vigilant so that if we do it, we do it right."