MIDDLESBROUGH are confident of extending Daniel Ayala's time on Teesside beyond the end of this week, but Rhys Williams' future has grown increasingly uncertain in the wake of increased interest from Swansea City.

Ayala's loan from Norwich City is due to expire on Thursday, but with the 23-year-old defender having once again proved his value in Saturday's 1-0 win over Charlton Athletic, there is a strong desire to retain his services to aid a promotion push that is gathering momentum by the week.

Boro chief executive Neil Bausor has been involved in a series of discussions with his counterparts at Carrow Road, with a loan until the end of the season and a permanent transfer both currently on the table.

The latter would be the preferred option provided an acceptable fee can be agreed, with an agreement of one kind or another anticipated before Boro head to Championship leaders Leicester City on Saturday.

“We're near to a deal to keep him,” said Boro boss Aitor Karanka. “The club is working to keep him here, and he is an important player for me. The most important thing is that the club are doing everything they can. Would it be another loan or a permanent signing? We are working on lots of options.”

While Ayala looks almost certain to be a Boro player beyond the end of January, the same can no longer be said of Williams after Swansea officials formally registered their interest at the end of last week.

The Swans have coveted Williams for almost two years, but their previous interest was rebuffed along with similar inquiries from Burnley. However, injuries to Jonathan de Guzman and Jose Canas have persuaded Michael Laudrup to make a renewed approach, and the Dane is understood to be willing to pay up to £2m in order to secure Williams' services.

Boro would rather not lose the versatile Australia international, especially as his last two defensive displays have arguably been his best of the campaign. There is no financial necessity to sell players, but with Karanka keen to reduce the overall size of his squad and the Spaniard's current budget close to the club's financial fair play limits, it would be no surprise to see Williams depart before the transfer window closes.

“I don't know if there's been an offer,” said Karanka. “Rhys is my player, and he's been an important player in the last two or three games. I'm happy with him, but at this moment, I don't know (what will happen).”

Williams' departure would create an opening for another acquisition, with a new centre-forward at the top of Karanka's wanted list.

There has been further contact with Genk over the future of Belgium international Jelle Vossen this month, but competing interest from Premier League strugglers Cardiff City has reduced Boro's chances of landing the 24-year-old.

Genk turned down Boro's £4m offer for Vossen in August, and since then, the striker has bolstered his reputation further with 15 goals in all competitions.

He is keen to play at as high a level as possible in order to force his way into Belgium's World Cup squad, and Cardiff's interest will make it much more difficult for Boro officials to persuade him to play in the Championship during the second half of the season.

If Boro do manage to recruit a new striker this month, they will consider offers for Lukas Jutkiewicz, with Championship rivals Burnley and Brighton both having registered an interest.

Blackburn have also discussed a possible swap deal involving Ruben Rochina, although their permanent purchase of Rudy Gestede has dampened their interest in Jutkiewicz.

Karanka has completed two loan signings this month, but neither Kenneth Omeruo nor Nathaniel Chalobah was involved in Saturday's 18-man squad.

Omeruo is short of match fitness having only recently returned from injury, while Chalobah only trained with his new team-mates for the first time on Friday, but it was still a surprise to see neither at least make the substitutes' bench.

They will surely be involved in some capacity against Leicester, although Karanka insists he has not given Jose Mourinho any assurances about the level of their involvement in the second half of the campaign.

“I don't have to explain anything to Jose,” he said. “He knows how it is. Maybe if we were losing games and the two weren't playing, he might be on the phone to me, but we're winning.

“It's the kind of problem that I want. We're delighted to have brought the two players from Chelsea, and I'm confident they'll fit in well here. It's a chance for them to get some experience under their belt. But they have a problem in that the team's playing very well and they know that. It's difficult for them.”