KADER Mangane will meet with Sunderland officials this weekend to complete his move from Saudi Arabian club Al-Hilal.
The Black Cats have agreed a loan deal until the end of the season, with a view to a permanent transfer worth around £2m in the summer.
Al-Hilal have accepted Sunderland's offer for the 29-year-old, who is due to finalise personal terms and undergo a medical within the next 48 hours.
Martin O'Neill has been desperate to reinforce his defensive options this month, and the need for a new centre-half intensified when Carlos Cuellar joined Wes Brown on the long-term injury list last weekend.
Mangane, who has been capped 15 times by Senegal, made more than 100 appearances for French Ligue One side Rennes before moving to Al-Hilal last summer.
At six foot five inches, he is a physically imposing defender who has been likened to former Blackburn skipper Christopher Samba in terms of physique and playing style.
"We have made inquiries," said O'Neill, ahead of this afternoon's Premier League home game with West Ham. "He's a lad who went out to the Middle East from Rennes and we've made a number of inquiries about his position.
"In fairness, we've inquired about a number of players. At this stage, that's as far as it's gone. We've talked about the possibility of a loan until the end of the season. Beyond that, it would depend on performances and things like that.
"In terms of the centre-half position, we're a bit short. Wes has been out for a long time and you wouldn't say that in the foreseeable future he's going to be back and in contention for us. We've been a bit short in that department, so we're looking to see if we can strengthen there."
Mangane is set to become Sunderland's second signing of the transfer window following the £3.5m arrival of Alfred N'Diaye on Wednesday.
N'Diaye will be named in today's squad provided the Black Cats receive his international clearance at least an hour before kick-off, and with Jack Colback set to replace the injured Danny Rose at left-back, the France Under-21 international could even be thrust straight into the starting line-up.
O'Neill travelled to Istanbul to watch N'Diaye play for Bursaspor against FC Twente in August, and while the midfielder did not do enough in that game to persuade the Sunderland boss to rush through a summer deal, his performances in the subsequent four months have convinced his new manager he is capable of succeeding in the Premier League.
"On the night we were there, he didn't play fantastically well," said O'Neill. "But we've kept an eye on it ever since and for the price we paid, we're happy.
"He's athletic, he can cover a lot of ground and while I think there's room for improvement in technique, that improvement is something he's really keen to make.
"I feel he can give us the sort of athleticism and vitality around the pitch that sometimes we maybe feel as though we've been missing.
"He can improve aspects of his game. Sometimes, in his willingness to try to do things, he goes into positions where he won't be able to receive the ball. But he'll be a great signing, he really will be."
Provided Mangane follows N'Diaye into the Stadium of Light at the start of next week, O'Neill's next priority will be to sign a striker.
Swansea's Danny Graham remains his preferred target, although Norwich, QPR and West Ham have also indicated a desire to bid for the former Middlesbrough trainee.
With Fraizer Campbell on his way out of the Stadium of Light provided another forward arrives before the end of the month, Connor Wickham is currently the only viable alternative to first-choice forward Steven Fletcher.
The pair combined superbly in the final half-hour of last weekend's FA Cup draw at Bolton, and there must be a temptation for O'Neill to start with both strikers alongside each other this afternoon.
With Stephane Sessegnon available after missing the trip to the Reebok Stadium, though, it is much more likely that the Benin international will start behind Fletcher, who is expected to return to his lone-striker role.
The forgotten man amongst Sunderland's forwards is Louis Saha, with O'Neill admitting the 34-year-old has struggled to make an impression since joining on a short-term deal in the autumn.
"When Louis first came to the football club, I told him I wasn't expecting miracles of him," he said. "He'd done no pre-season training, but I was hoping that over a period of time, he would come in here and make an impact.
"There was talk about us being interested in (Kevin) Davies last season, and I thought he might have been able to come in and do a half-decent job himself, but also help improve the young centre-forwards like Connor Wickham.
"It's been really tough for Louis. In training, in the small-sided games, he's been absolutely terrific. He's a bit disappointed that he hasn't been able to take that onto the field.
"Like everything else, he's getting a bit older and he's found the going a bit difficult. It's not a major surprise to me really."