Roberto De Zerbi said his Brighton side are playing "a different sport" this season as he grapples with a crowded fixture list and growing injury concerns in the club's debut European campaign.
Brighton lost Pervis Estupinan during Saturday's 6-1 trouncing by Aston Villa, with the defender likely to be out for "a long time", while Solly March, Pascal Gross, and captain Lewis Dunk have also missed games recently.
Brighton have regularly made seven or more changes between fixtures in the early weeks of this season, though it largely has not disrupted their rhythm as they sit sixth in the Premier League having won five of their first seven games.
However, as well as losing heavily at Villa they were beaten at home on their Europa League debut by AEK Athens, lending added importance to Thursday's game away to Marseille.
De Zerbi said that while he is reluctant to make wholesale changes, he can see little other option as the games mount up and his squad becomes stretched.
"I don't like before the game to change so many players," he said. "If you play with the same eight or 11, you can play better. But I have to do it.
"Lewis played in the national team, then after three days played another big game at Old Trafford and then we lost him for a very important game (AEK Athens).
"I don't want to put my focus on Premier League or Europa League, we have to compete every game in every competition. But we have many difficult situations. Solly March last season finished in a bad way with injury. This season, I have to manage him.
"Pascal Gross the same, he played in the national team (for Germany) then he spent the last period (injured). (Adam) Webster, (Danny) Welbeck, I have to manage them, because they can't play two games in threeRead on irishexaminer.com