Slaven Bilic has reinvigorated the East Londoners and narrowly missed out on a trip to Wembley after being held by a late goal against Manchester United at Old Trafford before losing 2-1 in the replay at Upton Park on Wednesday night.
They will hope to keep their hopes of Champions League qualification alive with a win over Sunday's opponents.
'The lads are enjoying it'
But big striker Carroll, who recently returned to form with a bang as he fired a hat-trick against Arsenal, has told the club's official website what he believes has been the key to West Ham's success this season.
“He (Bilic) has changed a lot and brought all the lads together and with all the staff he’s brought in, it’s been very good," Carroll told whufc.com.
"With the way we’ve played this season, it’s shown he has brought in the way he wants us to play and the lads are enjoying it.
“When the lads come into training, wherever we’re from we’re all sat on different tables and there are no separate groups.
"At the training ground, we’re all mates and all go on the pitch together as a team and work together.”
Hammers look to outfox the Foxes
Claudio Ranieri's side have proved a tough nut to crack all season and could all but seal an astonishing Premier League title with a victory over the Hammers.
West Ham themselves have been hard to beat this season, losing only six games.
Bilic's side will be looking to bounce back after the disappointment at slipping out of the cup midweek, their first defeat in 10 games.
West Ham's bitter rivals Tottenham Hotspur will also be cheering on the Hammers who could inadvertently let their London adversaries back into the title race.