Chris Coleman will need to time to turn around the situation at Sunderland, his predecessor Simon Grayson has told the BBC.
Coleman is set to be confirmed as the new Sunderland manager on Sunday after agreeing a deal to take over at the club, who are bottom of the Championship.
Reports said the ex-Wales boss took first-team training on Sunday, less than 24 hours after a 2-2 home draw with Millwall.
That result made Sunderland the first team in English football history to go 20 home games without a win.
And Grayson warned that it would be a long process for the former Wales boss to turn the club around.