Simon Grayson eager to keep impressive partnership together amid transfer speculation

Cattermole has made a fine start to the season

The Gabon midfielder is one of a number of potential targets for the French side, who are pressing ahead with a deal for Celta Vigo midfielder Pape Cheikh Diop.

Ndong has impressed alongside Sunderland stalwart Lee Cattermole in the heart of Sunderland's midfield, allowing Simon Grayson to play with two up front and increase the side's attacking threat.

The Black Cats have a number of options in that position but Ndong's athleticism would be difficult to replace.

Grayson had praise for Cattermole and hopes he will be able to continue playing them together after the transfer window shuts.

He said: "I've been really pleased with them. Catts has just been pleased to get some football under his belt after being out for so long, and it is testament to him that he has been available for all the games so far.

"They complement each other – Didier's energy and enthusiasm rubs off on other people. They are a good partnership at this moment in time and I hope that we can keep hold of them."

The pair are likely to continue on Saturday evening against Leeds United, despite the Black Cats boss admitting that fatigue could force changes to his side.

The Sunderland boss will look for his side to maintain the attacking threat they carried on the opening night of the season against Derby County, but has warned that his side will have to maintain their defensive shape.

That will be particularly crucial against last season's top scorer Chris Wood, who has been the subject of multi-million pound bids from Premier League side Burnley in the last week.

Grayson said: "You still have to get the right balance so you don't go to gung-ho and leave yourself vulnerable.

"Leeds have got some good players and can play on the counter-attack as well.

"We want to be on the front foot, dictate play, and get the crowd behind us, but also make sure that we keep the back door shut and that we don't concede on the counter-attack.

"Wood was the leading goalscorer in the Championship last year, so we have to be aware of his threat."