Arsene Wenger was without eight players for Sunday's 2-2 Premier League draw with Liverpool at Anfield.
Mesut Ozil, Jack Wilshere, Aaron Ramsey and Mikel Arteta were among the absentees as Martin Skrtel's late header denied Arsenal all three points.
Arsenal are sixth in the table and have reached the last 16 of the UEFA Champions League, with Monaco standing in their way of a place in the quarter-finals.
Midfielder Flamini believes the London club will need a full complement of players in order to make it a memorable season.
He told the club's official website: "It would be crazy to think [we won't improve] because we lost so many key players and having them back is very important for the team.
"We definitely need them because in the championship and the last stages of the Champions League, you cannot do it with 11 players. You need 25 so it is important for us to have them back.
"The season is going to be long and we are only just arriving at Christmas now. I am very confident in the team, very confident in the quality we have because we have a few top players.
"The most important thing is to recover well and be ready for the next game. In probably 10 days, we have three or four games so it is going to be a lot. We have to recover well for the next game and if we are ready, it will be fine."
Arsenal face London rivals QPR on Friday and then face another capital club, West Ham, two days later at Upton Park.
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