The visitors, meanwhile, are seeking to return to winning ways as they bid to stay in the mix to secure a place in Europe for next season.
Match preview
After ending an eight-game winless run with a 2-1 home victory over Osasuna, Rayo Vallecano suffered their 10th La Liga defeat of the season at the hands of Real Sociedad last weekend, losing 2-1 in San Sebastian.
Los Franjirrojos opened the scoring courtesy of a 57th-minute strike from Isi Palazon, but Sociedad restored parity just two minutes later through Alexander Sorloth before an own goal from Florian Lejeune nine minutes from time completed the comeback for the hosts.
Andoni Iraola's side were challenging for a top-six finish earlier this year, and while hopes of European qualification remain alive, their slump in form over the last few months has seen them slip to nine in the La Liga table, seven points behind Villarreal in sixth place.
Nevertheless, Rayo are still on course to improve on last season's 12th-place finish and either match or better their highest-ever La Liga position of eighth place achieved in the 2012-13 campaign, with just one point separating them from Osasuna in eighth.
Los Franjirrojos will be optimistic of coming away with a positive result on Wednesday as they are unbeaten in their last three meetings with Barcelona, with back-to-back 1-0 triumphs last season followed by a goalless draw at Camp Nou back in August.
Barcelona ended a three-game losing run without scoring in all competitions when they secured a slender 1-0 home victory over Atletico Madrid last weekend.
Ferran Torres scored his first goal at Camp Nou since October and the only goal of the game on the stroke of half time to help the Catalan giants claim their 24th La Liga win of the campaign - their highest top-flight win tally after 30 games since 2015-16.
Barca currently sit 11 points clear of reigning champions Real Madrid in second place and they are guaranteed to lift the La Liga title if they come out on top in five of their final eight games of the season.
Xavi's side have only lost two league games all season but both of those took place on the road, with a 3-1 El Clasico defeat to Real Madrid in October followed by a shock 1-0 loss to Almeira in February.
Barcelona's chances of success will be boosted if Robert Lewandowski can find his scoring boots; the Polish striker has found the net just twice in his last eight games across all competitions, drawing a blank in each of his last four outings, and both goals during this run were scored in the 4-0 away win over basement club Elche at the beginning of this month.
Rayo Vallecano La Liga form:
L
D
D
L
W
L
Barcelona La Liga form:
W
W
W
D
D
W
Barcelona form (all competitions):
W
W
L
D
D
W
Team News
Rayo Vallecano forward Radamel Falcao, who has scored four goals in six previous meetings with Barcelona, is ruled out with a muscle injury, while Santi Comesana will serve a one-match ban after picking up his fifth yellow card of the season last time out.
However, centre-back Alejandro Catena and winger Alvaro Garcia are both available for selection after serving one-game suspensions, and the duo are set to return to the first XI at the expense of Abdul Mumin and Andres Martin respectively.
Raul de Tomas was handed just his fourth league start of the campaign last weekend, but the striker could be replaced in the starting lineup by Sergio Camello.
As for Barcelona, Ousmane Dembele, Sergi Roberto (both hamstring) and Andreas Christensen (calf) all remain sidelined with injuries, while Sergio Busquets will serve a one-match suspension due to an accumulation of yellow cards.
The absence of Busquets could see Franck Kessie recalled to the starting lineup to operate in the pivot role, with Frenkie De Jong, Gavi and Pedri also battling for a start in centre-midfield.
Pedri will also compete with Torres and Ansu Fati for a place on the left flank, while Lewandowski is expected to continue in attack despite his poor run of form in front of goal.
Rayo Vallecano possible starting lineup:
Dimitrievski; Balliu, Lejeune, Catena, F. Garcia; Ciss, Valentin; Palazon, Trejo, A. Garcia; Camello
Barcelona possible starting lineup:
Ter Stegen; Kounde, Araujo, Alonso, Balde; Gavi, Kessie, De Jong; Raphinha, Lewandowski, Torres
We say: Rayo Vallecano 1-2 Barcelona
There has been little to separate the two teams in recent meetings, with Rayo Vallecano coming away as the happier side in each of the last three encounters, and they will be confident of causing another upset on Wednesday in front of their home supporters.