Barcelona's Spanish forward #19 Lamine Yamal injured. AFP
The 17-year-old has been sidelined since early November with an ankle problem and Barcelona have picked up just one point from the two league games he missed in that time.
"Lamine Yamal is back and he's ready to play. We haven't decided yet if he'll start, but he will play," Flick told reporters ahead of Saturday's game.
Yamal has scored six times in 16 total appearances this season and provided eight assists.
Table-toppers Barcelona have failed to win any of the three matches he has not started in La Liga, losing 4-2 to Osasuna in September when he was on the bench.
Barcelona are four points clear of Real Madrid but have played a game more than the defending champions.
Flick also said Uruguayan defender Ronald Araujo is nearing a comeback after undergoing surgery in July for a hamstring injury he sustained while playing for his country at the Copa America.
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