Sunderland have stepped up their interest in Wigan midfielder Lee Cattermole by tabling a formal offer.

Press Association Sport understands the Black Cats have followed up former Latics boss Steve Bruce's interest in the 21-year-old by submitting an undisclosed offer.

Wigan chairman Dave Whelan insisted earlier in the summer that the England Under-21s international was not for sale, and it remains to be seen if he can be prised away from the club he joined from Middlesbrough last summer for £3.5million.

Sunderland boss Bruce is already hoping to push through his first summer signing over the weekend, after agreeing a fee with Manchester United for Fraizer Campbell.

It is understood United have accepted a bid of around £5million for the England Under-21s international, who has been courted by Hull in recent weeks.

Campbell is expected to head for the north-east to undergo a medical and discuss personal terms as Bruce steps up his efforts to strengthen the squad he inherited from Ricky Sbragia.

The Huddersfield-born 21-year-old has made just four senior appearances for United but impressed during a loan spell at Hull during the 2007-08 season, when he scored 15 goals in 37 appearances.

He spent much of last season at Tottenham after joining the club on a temporary basis as part of the deal which took Dimitar Berbatov in the opposite direction.

Bruce has been targeting strikers throughout the summer, after the Black Cats decided not to take up an option on Djibril Cisse.

He is thought to have tabled an offer in the region of £11million for Portsmouth's England international Peter Crouch, and the Wearsiders have a long-standing interest in Spurs marksman Darren Bent - although it remains to be seen whether or not they are prepared to meet Harry Redknapp's asking price for the player.