TEAM news is vital this weekend but in FA Cup ties it's also important to see what teams are going to be at full strength.
This gives you some idea about who's on and who's out but keep an eye on managers' comments to see how they are approaching games.
Birmingham v Swansea
Recent loan signing Albert Rusnak is set for his Birmingham debut after being cleared to play by Manchester City. Midfielder Tom Adeyemi (back problem) is available for the first time this calendar year. Peter Lovenkrands (groin) is also back in the fold but Kyle Bartley, who has recovered from a hamstring problem, cannot face his parent club. Amari'i Bell is cup-tied while Jonathan Spector (thigh), Akwasi Asante (hamstring), Neal Eardley and David Murphy (both knee) remain in the treatment room.
Pablo Hernandez (hamstring) and Jonathan de Guzman (calf) are set to return from injury for the Swans but Nathan Dyer, Michel Vorm, Michu, Jose Canas and Garry Monk all remain on the absentee list.
Bolton v Cardiff
Forward Andre Moritz will come back into contention after missing his side's 7-1 demolition by Reading last weekend with a knee injury. His return to the squad would be welcome given Jermaine Beckford (hamstring) is still absent with a hamstring injury and David Ngog is close to a move to Premier League outfit Swansea which could possibly materalise before this weekend's game. USA international Stuart Holden (knee) is still sidelined and the midfielder is due to return to his home country next week for the next stage of his rehabilitation, while full-back Marc Tierney (foot) is a long-term absentee.
Cardiff boss Ole Gunnar Solskjaer could hand Magnus Wolff Eikrem and Mats Moller Daehli full debuts. Club captain Mark Hudson and full-back Declan John could also feature having missed out on a place in the starting XI at Manchester City.
Bournemouth v Liverpool
Bournemouth will have keeper Lee Camp available, having been ineligible for the third-round win over Burton because he had not been signed when the tie was originally due to be played. Cherries boss Eddie Howe could select the same line-up that drew 1-1 with Watford.
Injury to right-back Glen Johnson means Liverpool manager Brendan Rodgers is forced into another defensive reshuffle. Jon Flanagan could return from a hamstring injury while Martin Kelly is the other option to fill in. Goalkeeper Brad Jones will start in place of regular first-choice Simon Mignolet. There is a doubt over midfielder Joe Allen but defenders Daniel Agger (calf), Jose Enrique (knee) and Mamadou Sakho (hamstring) are all still out, while midfielder Lucas Leiva (knee) is set for a lengthy spell on the sidelines.
Manchester City v Watford
Man City top scorer Alvaro Negredo (shoulder) and playmaker David Silva (hamstring) will both miss out but defender Micah Richards could be in contention after hamstring trouble. Goalkeeper Costel Pantilimon is likely to continue and youngster Marcos Lopes could get another chance. Midfielder Samir Nasri is the only serious injury absentee due to a knee injury.
Watford are without Lewis McGugan and Iriney as they attempt to become the first English club to win away at City this season. McGugan is ruled out with a thigh problem while Iriney has a groin strain. They join suspended duo Fitz Hall and Alexander Merkel and the cup-tied Hector Bellerin on the sidelines. Marco Cassetti has been passed fit after overcoming the knee problem that has kept him sidelined since the original third-round tie against Bristol City at the start of January, while loanee Mathias Ranegie could make his Hornets debut.
Port Vale v Brighton
Joe Davis is ineligible for Port Vale and Carl Dickinson begins a two-match suspension after he received his 10th yellow card of the season during the league win over Oldham. Florent Cuvelier suffered knee ligament damage on his debut against the Latics last weekend and the on-loan Sheffield United midfielder will miss the remainder of the season. Chris Lines could take his place after serving a ban, while Gavin Tomlin could also return to the squad after injury.
Brighton could welcome Will Buckley (hamstring) back into their squad after a month out. Fellow wideman Kazenga LuaLua (hamstring) is also on the mend but the trip may come too soon while midfielder Andrew Crofts (knee) and strikers Craig Mackail-Smith and Will Hoskins (knee) are still out – although the latter pair are back in training after long-term absences. Youngsters Adam Chicksen, Solly March and Jeffrey Monakana could be involved if boss Oscar Garcia opts to rest players, but Liam Bridcutt's participation remains in doubt with the midfielder angling for a move away from the club.
Rochdale v Sheffield Wednesday
Rochdale defender Ollie Lancashire is a major doubt after he limped out of the midweek draw at Chesterfield due to an unspecified injury. He was replaced by Rhys Bennett, who could start in the fourth-round tie although Ashley Eastham will also be in contention. Manager Keith Hill has no other new injury or suspension problems.
Sheffield Wednesday will be without striker Connor Wickham because the on-loan Sunderland forward does not have permission to play in the competition. Another forward, Caolan Lavery, is available and is expected to resume up front. Midfielder Giles Coke will return to contention following a hamstring injury while on-loan goalkeeper Damian Martinez could return in place of Chris Kirkland. The Owls have no new injuries, but defenders Lewis Buxton (groin), Kamil Zayatte, Martin Taylor (both ankle) and Anthony Gardner (Achilles) are all still out.
Southampton v Yeovil
Dani Osvaldo will not be available for selection for Southampton after the striker was given a two-week ban by the club following a training-ground bust-up. The 28-year-old was due to return to the squad after serving a three-game suspension but will now sit out another three Saints fixtures. Saints have a Premier League clash with Arsenal on Tuesday night so could rotate their team, but there will definitely be no place for defender Dejan Lovren, forward Gaston Ramirez (both ankle) or midfielder Victor Wanyama (calf).
Yeovil will be able to field loan signing Ishmael Miller after being given the green light to feature by his parent club Nottingham Forest. There will be a change at left-back after Zoumana Bakayogo returned to Leicester having damaged his cruciate ligament on his debut at Birmingham. With Liam Davis sidelined due to a broken toe, Jamie McAllister or Luke Ayling look set to step in. Ed Upson is clear of his ankle problem and came through an appearance in a friendly against Plymouth unscathed and he is pushing for a start but Matteo Lanzoni is cup-tied.
Southend v Hull
Southend expect Ryan Leonard and Barry Corr to shake off niggles. Both were on target in the 3-0 win over Chesterfield at the weekend but ended the game with a foot and a calf knock respectively. Loanee Luke O'Neill is sidelined with a thigh problem suffered last weekend while skipper John White will see specialists on Monday about the shoulder injury that has seen him miss the Shrimpers' last two games.
Hull will be without cup-tied record signings Nikica Jelavic and Shane Long, meaning Yannick Sagbo and Matty Fryatt will be hoping to impress at Roots Hall. Manager Steve Bruce will rotate his starting XI but is without Tom Huddlestone (suspended), James Chester (hamstring), Robbie Brady (groin) and Sone Aluko (Achilles).
Stevenage v Everton
Stevenage are hopeful Filipe Morais will be fit to face Everton. The winger suffered a dead leg in the 1-0 defeat by Notts County last weekend but is expected to recover in time. Midfielder Dean Parrett (knee) is a major doubt while Boro have trimmed their squad this week by letting defender Ben Chorley join Portsmouth while striker Marcus Haber and full-back David Gray are on the transfer list.
Everton full-back Seamus Coleman has been ruled out due to the problem he picked up against West Brom on Monday. Defender Antolin Alcaraz (muscle fatigue), midfielders Ross Barkley (broken toe), Steven Pienaar (groin), Gerard Deulofeu (hamstring), Darron Gibson (knee) and forward Arouna Kone (also knee) remain sidelined.
Sunderland v Kidderminster
Argentina internationals Oscar Ustari and Santiago Vergini will make their debuts for Sunderland having signed for the club earlier this week. Poyet intends to make wholesale changes with Stoke due at the Stadium of Light in a crucial league fixture on Wednesday night but only defender Carlos Cuellar (hip) and keeper Keiren Westwood (shoulder surgery) are unavailable.
Kidderminster will be without Adrian Cieslewicz and Callum Gittings. New signing Cieslewicz is cup-tied having already played in the competition this season for Wrexham, while midfielder Gittings has been sidelined since the goalless draw with Peterborough in the original third-round tie due to hamstring and shoulder injuries. Marvin Johnson is set to carry the burden in attack again having replaced Joe Lolley, who hit the winner in the replay against Posh before completing his switch to Huddersfield.
Wigan v Crystal Palace
Uwe Rosler has confirmed Nick Powell will be on the bench for Wigan, having played through the pain barrier against Doncaster last weekend after picking up several knocks. New loan signing Josh McEachran will also not play, with Latics boss Rosler instead putting him on a specific training plan to improve his fitness. Defender Tyias Browning, borrowed from Everton, does not have permission to play while Rob Kiernan is cup-tied and the likes of Shaun Maloney (shoulder) are still absent.
Paddy McCarthy is expected to make the Palace squad after groin trouble. Boss Tony Pulis is set to make some changes but Jerome Thomas and Kagisho Dikgacoi are still suffering from calf problems and Jack Hunt (ankle) and Glenn Murray (knee) are out.
Huddersfield v Charlton
Huddersfield strikers Nahki Wells and Joe Lolley are both ineligible after appearing in earlier rounds of the competition for Bradford and Kidderminster respectively. Forward Martin Paterson (thigh) and defender Joel Lynch (groin/hip) remain doubtful, but leading scorer James Vaughan could return to the starting line-up after stepping off the bench at QPR last week following a five-game lay-off due to an ankle injury. Club skipper Peter Clarke, sidelined since early November, is back in training following knee surgery.
Charlton can include Standard Liege loanees Yohann Thuram-Ulien and Astrit Ajdarevic to their squad. The duo made their debuts at Middlesbrough last weekend but were ineligible to face Oxford in Tuesday's third-round replay as they were not signed before the original tie. Boss Chris Powell must decide whether to recall Thuram-Ulien or stick with Ben Alnwick, who returned in goal against Oxford after recovering from illness. Defenders Chris Solly and Richard Wood could return after they were rested in midweek but Rhoys Wiggins is suspended and Marvin Sordell (hamstring) and Leon Cort (knee) are injured.