Tottenham defender Younes Kaboul is having a medical on Wearside as Sunderland attempt to clinch a second major signing inside 24 hours.
Press Association Sport understands the £5million-rated Frenchman was undergoing tests on Thursday afternoon with a view to completing a move.
Kaboul rejected the chance to join the Black Cats seven years ago when the club, then managed by Roy Keane, made a joint £23million offer for him, Pascal Chimbonda, Teemu Tainio and Steed Malbranque.
At the time, his agent Rudy Raba was quoted as saying: "Younes wouldn't join Sunderland even if there was an earthquake. We have more interesting options than Sunderland. Don't even think about it."
Belgium defender Nicolas Lombaerts insists a failed medical was not behind the collapse of his proposed move to Sunderland.
The Zenit St Petersburg player is understood to have been on Wearside on Tuesday, and rumours later began to circulate that the deal had been shelved because of an issue picked up by medics.
However, the 30-year-old is adamant that it was his decision to pull the plug on a #5million transfer.
Lombaerts told www.sporza.be: "I've made the choice not to move to Sunderland. The story of the medical testing is not right."
Sunderland, as is their policy on transfers, have not commented on the situation, although sources close to the club have confirmed the breakdown in talks.
Meanwhile, the Black Cats are hopeful of concluding an £8million swoop for Dynamo Kiev's Holland international midfielder Jeremain Lens after he headed for Wearside on Wednesday.
Dynamo Kiev midfielder Jeremain Lens is expected on Wearside for a medical on Wednesday amid mixed news on the transfer front for Sunderland head coach Dick Advocaat.
Press Association Sport understands the Holland midfielder was heading from Ukraine to the north-east on Tuesday night after the two clubs agreed a fee in the region of £8million.
However, as the Black Cats prepared to push home their interest in the Dynamo man, sources close to the club have indicated that their interest in Zenit St Petersburg defender Nicolas Lombaerts has been shelved because of an issue picked up by medics.
Rumours that the 30-year-old Belgium international had failed a medical began to circulate on Tuesday evening, and it is understood that a proposed £5million transfer has now been put on hold.
Sunderland have been boosted by the news that midfielder Lee Cattermole has signed a new six-year deal with the club.
The former Middlesbrough man impressed Dick Advocaat in the latter stages of last season and was a key influence in their successful fight for survival.
Sunderland hope to complete the signing of Liverpool defender Sebastian Coates later this week.
The Black Cats are close to tying up a £2million deal for the 24-year-old Uruguay international, who had a loan spell at the Stadium of Light last season.
Press Association Sport understands talks are ongoing and that the club is hopeful of reaching a successful conclusion within days.
Coates is currently enjoying a break after Uruguay's involvement in the Copa America, but with just a year of his contract at Anfield to run, is expected to leave this summer.
Newcastle managing director Lee Charnley is facing a battle to make a summer transfer breakthrough after neighbours Sunderland entered the race to capture one of Steve McClaren's top targets.
It is understood that the Black Cats have made an offer of in excess of £11million for PSV Eindhoven's highly-rated midfielder Georginio Wijnaldum, a man identified by the Magpies' new head coach as a key acquisition following his appointment earlier this month.
Sunderland counterpart Dick Advocaat himself is understood to have made contact with the Dutch club to register his interest in the 24-year-old Holland international, who scored 14 Eredivisie goals last season as PSV cruised to the title.
In the process, he has firmly thrown down the gauntlet to Newcastle and Charnley, who has been charged with the task of doing the deals by owner Mike Ashley after identifying targets in a series of meetings with McClaren and chief scout Graham Carr.
Fans credit their popular manager's wife with allowing him to stay on in England for another year before retirement.Read the full story ›
Dick Advocaat has agreed to stay on as Sunderland manager, the Premier League club have confirmed.
It looked like the Dutchman was set to depart the club after announcing he would not continue in his role.
The main sticking point for the 67-year-old was getting his wife to agree to him staying at the Stadium of Light.
Advocaat had always said Sunderland would be his last job in club management, but he will now carry for another year.
DA: “It was a great feeling to be part of Sunderland in the last few months, the experience was something very special." (1/2)
DA: "After talking with Lee, Ellis and of course my family, we all agree it is the right decision." (2/2)
Dick Advocaat is set to perform a quasi-dramatic U-turn and remain as Sunderland manager.
The Dutchman kept the club in the Premier League after taking over from Gus Poyet.
Last month Advocaat announced he would not extend his deal at Sunderland, but it is now thought he has changed his mind.
Sunderland winger Adam Johnson has pleaded not guilty to four child sex charges.
Johnson is accused of three counts of sexual activity with a child and one of grooming at Durham Crown Court.
The trial will start on 24 August, it was confirmed.