The Robins are enduring a very tough patch in their season with many supporters turning against manager Nigel Pearson, whereas Millwall fans are in dreamland after defeating rivals Watford on Boxing Day.
Match preview
Millwall boss Gary Rowett has been cautious all season of getting carried away with talk of a promotion charge with his closely-knit squad, however after some of their recent results the ex-Birmingham City manager may need to face such discussions pretty soon.
The Lions have lost just twice in their last 12 Championship fixtures, with their most recent match ending in a 2-0 success against Slaven Bilic's Watford at Vicarage Road on Monday afternoon.
Andreas Voglsammer opened the scoring for the visitors with what is the German's first-ever goal in English football, before Dutchman Zian Flemming netted his 10th goal of the season in the second half.
That victory catapulted Rowett's side into sixth in the second-tier standings by the end of play on Boxing Day, with his current group of players seeming more capable offensively than the ones who have failed to finish in the top six over the past three seasons.
Any extra attacking flair has not been traded for the club's traditional toughness, with Millwall possessing the best defensive record on home soil this campaign, having conceded just eight times in 11 matches at The Den.
Bristol City have now won only one of their last nine matches in all competitions after being convincingly beaten by Carlos Corberan's West Bromwich Albion on Boxing Day at Ashton Gate.
The under-pressure Pearson admitted his side were second best for the majority of proceedings in Somerset and understood some of the discontent from supporters which was directed towards him.
That defeat has left the Robins 18th in the Championship, just two points ahead of Blackpool who occupy the highest of the relegation places, meaning the importance of the upcoming trip to Millwall can not be overstated.
City have suffered from Austrian Andreas Weimann not reaching the performance levels of his 22-goal season of last campaign, with the 31-year-old occasionally being left out of the starting XI all together by Pearson.
Millwall Championship form:
D
D
W
L
D
W
Millwall form (all competitions):
D
W
D
L
D
W
Bristol City Championship form:
L
D
D
W
L
L
Bristol City form (all competitions):
D
L
D
W
L
L
Team News
Millwall will be without winger Callum Styles who suffered a calf injury in the defeat to Sunderland earlier this month, with the ex-Barnsley man expected to be back in action in early January.
A long-term absentee for Rowett's men is Ryan Leonard who has not featured since August after a serious hamstring injury - the club are targeting his return in January.
Andy King is a doubt for Bristol City after being forced off with a knock in the second half on Boxing Day, meaning Pearson could be forced to start Robert Atkinson at The Den - a player he has recently left out of matchday squads due to a lack of trust.
The Robins could do with the presence of Tomas Kalas in their backline but the medical team at Ashton Gate are wary of rushing the 29-year-old back from his calf injury too quickly, meaning he is unlikely to feature in this one.
Millwall possible starting lineup:
Long; McNamara, Hutchinson, Cooper, Wallace; Mitchell, Saville, Voglsammer, Flemming, Burey; Bradshaw
Bristol City possible starting lineup:
O'Leary; Vyner, Atkinson, Naismith, Pring; Weimann, Williams, James, Scott; Wells, Conway
We say: Millwall 2-0 Bristol City
Millwall are back at The Den after a successful trip to Watford and will be fully confident in collecting another three points on Thursday night.
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