Manuel Pellegrini makes four changes to the Manchester City side beaten by Arsenal last weekend, with Willy Caballero, Dedryck Boyata, Aleksandar Kolarov and Stevan Jovetic coming in, as Joe Hart, Martin Demichelis, Gael Clichy and Fernandinho drop to the bench.

Four changes too for Middlesbrough, with midfielder Dean Whitehead filling in at right-back for the injured Tomas Kalas. Tomas Mejias replaces Dimi Konstantopoulos in goal, while winger Albert Adomah and forward Jelle Vossen also come in. Veteran defender Jonathan Woodgate, who hasn't played since August, is on the bench.

Man City XI: Caballero; Zabaleta, Kompany, Boyata, Kolarov; Navas, Milner, Fernando Silva; Jovetic, Aguero.

Middlesbrough XI: Mejias; Gibson, Ayala, Friend; Tomlin, Clayton, Leadbitter, Whitehead, Adomah; Bamford, Vossen.

Tottenham boss Mauricio Pochettino makes nine changes to the side which huffed and puffed its way to a slender win over Sheffield United in the League Cup. Among the many changes, in comes Younes Kaboul, Roberto Soldado and Erik Lamela. Emmanuel Adebayor, captain on Wednesday, is relegated to the bench.

Leicester boss Nigel Pearson gives a full debut to £9m club record signing Andrej Kramaric, the Croatian partnering Leonardo Ulloa and Jamie Vardy up front - the Foxes clearly going in search of goals. There are five changes in all from the team which lost to Stoke last week, including a first start for 42-year-old keeper Mark Schwarzer, signed from Chelsea earlier in the month.

Tottenham XI: Vorm, Chiriches, Fazio, Kaboul (c), Rose; Capoue, Dembele; Townsend, Paulinho, Lamela; Soldado.

Leicester XI: Schwarzer, Simpson, Morgan, Moore, De Laet, Drinkwater, King, Vardy, Kramaric, Schlupp, Ulloa.

Chelsea are still aiming to win the quadruple - the Premier League, Champions League, FA Cup and League Cup - and boss Jose Mourinho has one eye on Tuesday's League Cup semi-final second leg against Liverpool.

He makes nine changes for the FA Cup tie against Bradford with only Gary Cahill and John Mikel Obi keeping their places. Didier Drogba, Petr Cech and Loic Remy are among those coming in, while 18-year-old Danish defender Andreas Christensen makes only his second start for the club.

Bradford City boss Phil Parkinson makes one enforced change as on-loan goalkeeper Jordan Pickford has not been given permission to play in the FA Cup by parent club Sunderland, so Ben Williams starts. Filipe Morais and Billy Knott, both former Chelsea academy players, also start.

Chelsea XI: Cech; Christensen, Zouma, Cahill, Azpilicueta; Ramires, Mikel; Remy, Oscar, Salah; Drogba (c).

Bradford City XI: Williams, Darby, McArdle, Davies, Meredith, Liddle, Morais, Halliday, Knott, Hanson, Stead

West Brom manager Tony Pulis makes three changes to the side that drew 0-0 at Everton last time out, including in goal where Boaz Myhill replaces Ben Foster. Defender Michael Dawson and midfielder Stephane Sessegnon also gets starts.

Birmingham boss Gary Rowett makes two changes, including the omission of winger Demarai Gray who has been the subject of a bid from Bournemouth. Former West Brom winger Lloyd Dyer is given a debut after signing on loan from Watford with top scorer Clayton Donaldson starting on the bench alongside Gray.

Birmingham XI: Randolph, Caddis, Morrison, Robinson, Grounds, Davis, Gleeson, Cotterill, Shinnie, Dyer, Novak.

West Brom XI: Myhill, Wisdom, McAuley, Dawson, Lescott, Yacob, Gardner, Brunt, Sessegnon, Anichebe, Berahino.

Anthony Shaw:, external Why would you take King off!? He's showing the Swansea defence up. Hope taking him off doesn't come back to bite us.

Join the debate on any of the hot topics from today's FA Cup at #bbcfacup, external on Twitter, text us on 81111 (UK only), or drop us a line on the BBC Sport Facebook, external or Google+ page., external

A change of tactic for Blackburn now? They are pinging balls into the area for Rudy Gestede and he just fails to reach Craig Conway's cross.

Garry Monk reacts to Blackburn's change with a substitution of his own - Jefferson Montero is on for his FA Cup debut, replacing Modou Barrow.

Former Scotland international Pat Nevin
BBC Radio 5 live at Ewood Park

"There must have been a temptation to keep Josh King on. His pace might have created a bit more space for Rudy Gestede, whose goal scoring has been superb this season. This is Gestede's chance to show that he can do, with a lot of big teams watching I'm sure."

Well, some relief for Swansea as the pacy Josh King goes off. The bad news? In-form striker Rudy Gestede is on in his place.

Hmmm, this might not be what Swansea want to see. Twelve-goal striker Rudy Gestede is getting ready to enter the fray...

Former Scotland international Pat Nevin
BBC Radio 5 live at Ewood Park

"David Dunn looks class. Every time he gets the ball he is looking for passes with his head up, he looks fantastic on the ball. He is seeing the passes more than anybody else and is constantly trying to find Josh King."

Blackburn are very much enjoying themselves as they continue to dictate play, but without really creating much in the final third. Marcus Olsson half-heartedly hits an effort well wide from distance to the sound of ironic cheers from the away fans.

BBC Radio 5 live

Image source, BBC 5 live

The league positions of Blackburn & Swansea were rather different on this date 20 years ago...

You would think David Dunn would be used to the colder climes of North West England but no, he is one of the few players out there with gloves on. Regardless, he is pulling the strings in midfield for Blackburn in this half and plays a teasing ball for Josh King to run on to. This time, Federico Fernandez manages to sweep the ball out of play.

Former Scotland international Pat Nevin
BBC Radio 5 live at Ewood Park

"Josh King is having such an impressive afternoon. He really is skinning the Swansea back line."

Image source, PA

End-to-end start to the second half as first Bafetimbi Gomis brings a high ball under control but sees his shot blocked on the edge of the area, before Josh King again uses his pace to leave his marker in his wake, breaks into the area but his shot is held by Lukasz Fabianski.

Former Wales international John Hartson
BBC Two Wales at Ewood Park

"I think we will definitely see one of Jordan Rhodes or Rudy Gestede come on for Blackburn. They are both in good scoring form, Gestede with 12 goals and Rhodes with eight. Josh King is playing really well, and is a real threat with his pace, but you would expect one of those two to come on and bolster the Rovers attack."

Will the second half prove as frenetic as the first? Blackburn get things back under way.

Former Republic of Ireland winger Kevin Kilbane
Football Focus

Image source, Getty Images

The Bantams' forward line could boast the experience of 31-year-old striker Jon Stead - could the much-travelled former Blackburn and Sunderland striker help spring a big upset?.

"For one reason or another it never quite happened for him, but he's still a very good player, he's played at the top level and has a lot of experience."

Former Wales international Robbie Savage
Football Focus

"Gary Rowett has a great aura around him, even playing with him at Leicester you could see he was studying football, there was never a doubt that he would make a success of being a manager."