It remains to be seen whether the Argentine attacker will start or feature as a substitute in the Clasico, but Dembele will not be involved after failing to make the squad as he recovers from an ankle injury. The French winger should be back for the trip to Athletic Club in La Liga on Sunday.
If Messi is left on the bench, Valverde could opt for youngster Carles Alena in a wide role, with winger Malcom another alternative.
Goalkeeper Jasper Cillessen, who usually starts for Barca in the Copa del Rey and was a hero as he saved a penalty in last Wednesday’s 6-1 win over Sevilla, is out with a calf problem.
That means Marc-Andre ter Stegen will feature in goal for Ernesto Valverde’s side, with 19-year-old Inaki Pena called up as his reserve.
Barcelona 4-3-3: Ter Stegen; Sergi Roberto, Pique, Lenglet, Alba; Busquets, Arthur, Rakitic; Messi (or Alena), Suarez, Coutinho
And Real Madrid…
Santiago Solari has a strong squad at his disposal for the Clasico, with only defender Jesus Vallejo out through injury.
Gareth Bale made his first start since returning from injury as Los Blancos beat Alaves 3-0 at the Santiago Bernabeu on Sunday, but the Welsh winger may have to settle for a place on the bench for the trip to Camp Nou.
Vinicius Junior is in line to play from the outset in what will be his first Clasico, having been cut from the matchday squad by former coach Julen Lopetegui in October’s 5-1 defeat at Camp Nou.
Lucas Vazquez, rested on Saturday, looks likely to feature on the other side, although Solari could also opt for Bale. Meanwhile, Toni Kroos should start in midfield after he sat out on Saturday.
Right-back Dani Carvajal, suspended at the weekend in La Liga, will return in place of Alvaro Odriozola, with Solari set to keep faith in youngster Sergio Reguilon over out-of-favour Marcelo on the left.
Keylor Navas, who has lost his place to Thibaut Courtois in La Liga and the Champions League, is first choice in the Copa del Rey this season and will start at Camp Nou.
Real Madrid 4-3-3: Navas; Carvajal, Ramos, Varane, Reguilon; Casemiro, Kroos, Modric; Vazquez, Benzema,