Sky Sports News sources understand that West Brom are closing on signing Liam Ridgewell on a three-year deal.
As reported last month, the Baggies and Fulham were thought to be chasing Birmingham's versatile defender.
Following their relegation to the Championship, the Blues would be willing to let Ridgewell - who is under contract until 2013 - leave at the right price.
The 27-year-old has made 138 league appearances for Birmingham since his £2million switch from Aston Villa in 2007.
If he does join Roy Hodgson's side, Ridgewell could be the second Birmingham player to switch to The Hawthorns with the Baggies also close to landing highly rated keeper Ben Foster.