Gabriel Martinelli will miss Arsenal Champions League clash with Porto on Tuesday with a foot injury.
The 22-year-old got into trouble during Arsenal 5-0 win over Sheffield United last weekend.
Martinelli missed training on Monday ahead of Tuesday last-16 tie as Arsenal try to win 1-0 in the first leg.
He missed Saturday 2-1 win over Brentford although Arsenal manager Mikel Arteta said he was positive the striker would be available for the game and was later seen holding a crutch. At the Emirates Stadium.
The Gunners must win by more than one goal to reach the quarter-finals.