Liverpool will be without midfielder Jordan Henderson for the Barclays Premier League clash with Stoke and his injury robs the Reds of a key player as they look to both make progress in the Europa League and push up the standings.
Lucas has not played since February after suffering a thigh strain but both he and Kevin Stewart could be available to face Stoke after proving their fitness in a friendly on Friday.
“Kevin Stewart could also play 45 minutes in this game. That’s what they needed, so we’ll have to make a decision.
“These two players are back and that’s very important for us. We have to make a decision about the line-up, about system and a lot of things, but in the end we will have players in this position for sure.”
Liverpool were ninth coming into weekend having picked up one point from their last two outings, but they do have at least one match in hand on all the teams above them.
A victory at Anfield would move them above eight-placed Stoke at the very least, but Klopp acknowledges his side will need the help of their fans as they play a second match in under four days.
“For sure, in a situation like this, you need the crowd 100 per cent,” he said.
“For us it will be a big fight. For this fight, we need each voice at Anfield.
“Hopefully we can create a big atmosphere because it will be really, really necessary.”
Stoke boss Mark Hughes feels his side have it in them to win every one of their six remaining games this season.
And Hughes, whose men have won four and drawn two of their last seven games, said ahead of Sunday’s contest: “Ideally we would love six wins.
“How realistic that is we don’t really know, but we have the potential to do that.
“It is a tough ask. We have tough games.
“But our intention is to try to win every one of them and see how far that takes us. We want to finish the season as strongly as we can.”
Last weekend’s action left Stoke – ninth at the end of both their two seasons so far under Hughes – in eighth place.
Regarding the push for a European berth, Hughes added: “It is something we aspire to and want to achieve.
“It is all about setting realistic targets at the beginning of the year and seeing how close to them you can get.
“Europe was one we always felt if we had a good run at we’d go close to.
“And, if we miss out this year, we’ll have a real go again next year, because that is where we hope the club will be in the future – always pushing for European places.”
Stoke have not won away in the league against Liverpool – who started this weekend a place and two points worse off than the Potters, with eight more top-flight games to play – since 1959.
They did, though, in January win 1-0 on the night at Anfield in the second leg of their Capital One Cup semi-final against the Reds before losing the tie on penalties.
They will have skipper Ryan Shawcross and Xherdan Shaqiri back available when they go in search of another victory at the ground on Sunday, but Glenn Whelan and Marko Arnautovic are doubts.
Defender Shawcross and winger Shaqiri are each set for their first appearance in three games after recovering from back and thigh problems respectively.
Midfielder Whelan sustained a back issue of his own last week getting out of his car that then forced him off against Swansea, a match which also saw forward Arnautovic pick up a knee injury.
Goalkeeper Jakob Haugaard, who made his Premier League debut in that contest, is set to remain in the first XI.
Watch Klopp’s pre-match press conference: