The absence means the 22-year-old misses at least four games and could be back for the away game against Manchester United in the Premier League on October 19.
Kulusevski should have returned from national team games - 1-4 against Serbia and 1-1 against Slovenia in the Nations League - with the thigh injury.
During the start of the season, Dejan Kulusevski has scored one goal and two assists in nine competitive matches.
CLIP: Kulusevski: "Having a tough time in our clubs"
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Dejan Kulusevski and Robin Olsen.
Photo: Bildbyrån.