By Alex Stevens

Rangers have made an enquiry for Sunderland striker Danny Graham, Football Insider sources understand.

The 30-year-old, who is currently on loan at Blackburn Rovers, is out of contract with the Premier League club at the end of the season.

A source close to the situation has told Football Insider that the Scottish giants have made contact in recent days about the player’s interest in a move to Ibrox in the summer.

Graham is available on a free transfer but would have to accept a drop in wages to make the move to Rangers.

Ibrox manager Mark Warburton knows the much-travelled striker from their time together at Watford and is keen to pair him with leading scorer Martyn Waghorn as the club prepare for life in the top flight next season.

Graham finished top scorer at Watford and Swansea in his first full seasons at both clubs before moving to Sunderland in a £5million deal in January 2013.

The striker has only scored one goal for the Black Cats but has continued to net regularly during loan spells at Hull, Middlesbrough, Wolves and Blackburn.

The former England Under-20 international has scored six goals in 16 games at Blackburn, whom he joined on loan in the January window.

Warburton helped Waghorn lay down roots in Glasgow and he hopes to persuade Gateshead-born Graham to do the same.

In recent days Rangers have been linked with moves for Blackburn defender Grant Hanley and Liverpool midfielder Jordan Rossiter.

In other Rangers news, the club are lining up a big-money double swoop for a Premier League pair.