With a busy December ahead, the coach said he wanted "fresh legs and sharp decisions" as the club dealt with yet another wave of injuries.
Flick confirmed that Ronald Araujo would miss out after a stomach virus kept him out of two training sessions. His absence forced a defensive rethink, with Pau Cubarsi expected to partner Eric Garcia at centre-back, while Gerard Martin remained an option if further adjustments were needed.
The injury problems continued in midfield. Fermin Lopez, who had delivered important performances this season, was ruled out for around two weeks with a soleus injury. Flick admitted it was "a tough moment for him and for us".
Dani Olmo was set to take over as the main creative presence, with Marc Casado likely to rejoin Frenkie de Jong in the engine room. This shift would return Garcia to his natural defensive role after covering in the pivot recently.
There was positive news too. Pedri had completed his recovery and was expected to feature from the bench. But the major boost came in attack, where Raphinha was in line for his first start since returning from injury. Flick has said the Brazilian's comeback "gives us a different rhythm".
His return completed Barcelona's first-choice front three alongside the electric Yamal and the experienced Lewandowski, a trio the staff believed could "change the momentum of games".
Marcus Rashford remained a strong contender after his midweek bench role at Stamford Bridge, but all signs pointed to Raphinha reclaiming his place as Barcelona looked to strike with renewed intensity at the Spotify Camp Nou.
Diego Simeone has urged his Atletico Madrid players to embrace the challenge of facing Barcelona on Tuesday night, after offering sympathy to Hansi Flick following the Barcelona manager's emotional moment with Raphinha at the weekend.
Wojciech Szczesny has admitted he "had enough of this suffering" after years of battling the lingering effects of the double-arm fracture that changed his career, with the Barcelona goalkeeper revealing how the pain still affects him today.
Barcelona defeated Alaves 3-1 at the revamped Camp Nou on Saturday whilst Atletico beat Oviedo 2-0 to maintain the pressure on Real Madrid who play on Sunday.
Real Madrid and Girona both played their part in a dramatic La Liga weekend that also saw Villarreal surge, Betis silence Sevilla and Espanyol snatch a late winner.
