The 22-year-old spent half-a-season on loan with West Brom during the 04/05 Premiership season and he was a pivotal part of their great escape from relegation.
Rumours suggest Sunderland have beaten off competition from Sven Goran-Eriksson's Man City and Everton to sign the midfielder for a fee of £5.5m.
If Richardson were to sign on Monday, he would most certainly become Sunderland's second-most expensive player to date. That spot is currently occupied by new signing Michael Chopra.