The two Championship teams played out a 2-2 draw on Saturday, Blues netting a late equaliser to end a poor run of results since the turn of the year.
Match preview
Birmingham's and Blackburn's priorities currently lie elsewhere, Blues in constant takeover talks and looking to avoid a relegation scrap, with Blackburn bidding to remain in the promotion hunt in the Championship.
Nevertheless, that did not prevent the sides putting on an entertaining spectacle at Ewood Park at the weekend, the tie swinging back and forth throughout the 90 minutes.
Blues held an early advantage before finding themselves 2-1 adrift by 46 minutes, but a 90th-minute Jordan James goal earned the West Midlands side a share of the spoils.
From Blackburn's perspective, it was their second draw in succession after going 27 matches in the Championship without posting a single stalemate.
Jon Dahl Tomasson's side have now gone three games without a win, only prevailing twice in their most recent eight fixtures in all competitions.
Despite occupying fifth place in the Championship, Rovers are underdogs to retain a top-six spot in the long term unless they find the consistency that has been lacking since the start of the season.
Birmingham travelled to the North-West having posted five successive defeats in the second tier, their only victory since December 16 coming at Forest Green Rovers in the third round of the FA Cup.
Although they have an extra game on their schedule, John Eustace will feel that the joy of James's late goal could help Birmingham build some momentum going forward.
While they are six points above the bottom three, they are currently the worst performing team in the division and have played a match more than two of the sides below them.
Birmingham City FA Cup form:
W
D
Birmingham City form (all competitions):
L
L
L
W
L
D
Blackburn Rovers FA Cup form:
W
D
Blackburn Rovers form (all competitions):
L
W
W
L
D
D
Team News
Despite earning a draw at Ewood Park, Eustace may look to make changes to his Blues XI in order to introduce some fresh legs.
Hannibal Mejbri and Juninho Bacuna are both in contention to earn a recall in midfield, while Scott Hogan may get a run out ahead of Lukas Jutkiewicz.
The back five should stay the same with Eustace looking to build some stability in that area of the pitch.
Tomasson could take a similar approach with his Blackburn side with Sammie Szmodics potentially replacing Bradley Dack in the role behind the striker.
Jack Vale may come in for Sam Gallagher in that role, while Lewis Travis is an alternative in central midfield.
Birmingham City possible starting lineup:
Etheridge; Colin, Sanderson, Long, Trusty, Friend; Gardner, Bielik, Mejbri; Khadra, Hogan
Blackburn Rovers possible starting lineup:
Kaminski; Rankin-Costello, Carter, Wharton, Pickering; Buckley, Travis; Hedges, Szmodics, Brereton Diaz; Vale
We say: Birmingham City 1-2 (after extra time) Blackburn Rovers
With Birmingham having finally ended their dismal run against second-tier opposition, they will be confident of progressing through to the fifth round. However, Blackburn have history of bouncing back from disappointing results, and we feel that they could edge this contest, potentially after extra time.