SUNDERLAND have expressed an interest in Celtic's winger Scott Sinclair ahead of today's transfer deadline - and Leeds defender Laurens de Bock has undergone a medical at the Academy of Light.

It would be a major coup if the Black Cats could pull off the Sinclair deal, although the finances involved make it quite difficult.

Time is running out for Sinclair to leave the Scottish Premier League champions before the deadline, and there is known to be other interest in him from overseas. 

Celtic have let him know he can depart because he is no longer part of Neil Lennon's plans but only League One and Two clubs can still sign him before today's 5pm deadline if he wants to stay in England.

His reputed £30,000-a-week wage clearly makes things tricky for clubs at that level, and Sunderland have worked hard to move players on who earn such figures over the last 14 months.

What it will boil down to is how much Sinclair wants to play football, even at a lower level, and how much of a hit Celtic are prepared to take on his wages.

The 30-year-old would certainly be an exciting arrival to boost the League One promotion push after Saturday's 3-0 defeat at Peterborough.

Sunderland manager Jack Ross outlined after that game how he hoped to have a new left-back signed up this morning.

Swansea's Declan John was one of the favourites to arrive, while Sheffield Wednesday's Morgan Fox and Kilmarnock's Greg Taylor are two others who Sunderland have offered money for.

But over the last 24 hours it has emerged Leeds United's out of favour full-back de Bock is also on the radar.

Sources close to Elland Road have suggested a deal is likely to happen and Belgian has been on Wearside for the last 24 hours to finalise the switch.